UROLOGICAL ONCOLOGY Prognostic Significance of Blood Type A in Patients with Renal Cell Carci- noma Kyungtae Ko,1 Young Hyun Park,2 Chang Wook Jeong,2 Ja Hyeon Ku,2 Hyeon Hoe Kim,2 Cheol Kwak2* Purpose: In this study, we evaluated the prognostic significance of the ABO blood type in patients with renal cell carcinoma (RCC) who had undergone partial or radical nephrectomy. Materials and Methods: Information on the ABO blood type was obtained from 1750 patients with RCC. A total of 1243 men and 507 women (mean age, 55.41 ± 12.43 years) with RCC who had undergone partial or radical nephrectomy were enrolled in this study. The median follow-up duration was 35.0 months (interquartile range [IQR], 16.0–67.0). During the follow-up period, 271 patients experienced RCC recurrence, and 137 patients died from RCC. Results: Type A was the most common blood type (568, 32.5%), followed by type O (525, 30.0%), type B (464, 26.5%), and type AB (193, 11.0%). Generally, blood type was not associated with any clinicopathological factors. Unlike blood type O, the multivariate analysis of progression-free survival (PFS) showed that blood type non-O (A, B, and AB) was an independent prognostic factor for a worse outcome (95% confidence interval [CI]: 1.24– 2.37, hazard ratio [HR] = 1.71, P = .001; 95% CI: 1.08–2.13, HR = 1.51, P = .016; 95% CI: 1.03–2.43, HR = 1.58, P = .037, respectively). Cancer-specific survival (CSS) analysis showed that blood type A was an independent factor associated with a worse prognosis for CSS (95% CI: 1.05–2.64, HR 1.66, P = .031, respectively). Conclusion: The ABO blood type is significantly associated with PFS and CSS in patients with RCC following partial or radical nephrectomy. Blood type non-O (A, B, and AB) is an independent prognostic factor for a worse PFS outcome, and blood type A is an independent factor associated with a worse CSS prognosis. Key words: ABO blood group; Renal Cell Carcinoma; Prognosis; Prognostic Factor; Nephrectomy INTRODUCTION Renal cell carcinoma (RCC) is the most deadly ma-lignancy in urology. Approximately 30–40% of patients die from this disease.(1,2) In 2012, 338,000 pa- tients were newly diagnosed with RCC, and 143,000 patients died from RCC worldwide.(3) Recently, the diagnosis of smaller-sized early-stage renal masses has increased because of the development of radiological diagnostic tools and regular medical examinations. However, the incidence of RCC and the mortality rate per unit population have risen steadily.(4,5) There- fore, more attention is now being paid to RCC prog- nosis. The TNM Classification of Malignant Tumors stage is a strong prognostic factor in RCC. However, the TNM stage is not completely accurate as a prog- nostic indicator, as the prognosis of RCC varies widely between patients with same-stage tumors. Many clini- cians have been attempting to identify new prognostic factors, such as tumor size and Fuhrman nuclear grade. (6,7) Recently, we reported that body mass index (BMI) and nutritional status also impact prognosis in RCC.(8,9) Other factors, such as hematologic indices, inflamma- tory markers, and serum calcium level, have also been introduced as next-generation prognostic factors.(6) The ABO blood type is a classic prognostic factor in several malignant conditions. A correlation between the ABO blood type and gastric cancer was reported six- ty years ago.(10) Thereafter, the correlation between the ABO blood type and other malignancies, such as breast cancer, pancreatic cancer, lung cancer, and obstetric cancers, has been continuously reported.(11-14) The ABO gene encodes for glycosyl transferase, which catalyzes the transfer of donor sugar to the H antigen to form the ABO antigen. ABO antigens exist not only on erythro- cytes but also in other body tissues, predominantly in the endodermal epithelial lining and in some types of pa- renchymal cell lines, including those in the kidney.(15,16) Through membrane signaling, mediation of intercellular adhesion, or angiogenic effects, the ABO blood type may affect the progression or survival of patients with RCC. Previous reports have been inconsistent regarding the influence of the ABO blood type on the progno- sis of patients with RCC. Because these studies in- cluded small sample sizes, direct comparison with the ABO blood type was not evaluated. In this study, we evaluated the prognostic value of the ABO blood type in a relatively large cohort of patients with RCC Urological Oncology 2765 1 Department of Urology, Hallym University College of Medicine, Seoul, Korea. 2 Department of Urology, Seoul National University College of Medicine, Seoul, Korea. *Correspondence: Department of Urology, Seoul National University Hospital, 28, Yongon-dong, Jongno-gu, Seoul, Korea. Tel: +82 2207 22428. Fax: +82 2742 4665. E-mail: mdrafael@snu.ac.kr. Received January 2016 & Accepted March 2016 Vol 13 No 04 July-August 2016 2766 who had undergone partial or radical nephrectomy. MATERIALS AND METHODS Study Population We performed a cross-sectional retrospective study of 1763 consecutive patients who had undergone partial (n = 676) or radical nephrectomy (n = 1087) for RCC at a single institution from March 1999 to December 2011. Among the 1763 patients, ABO blood type in- formation was obtained from 1750 patients with RCC. This retrospective analysis of this patient popula- tion was approved by an Institutional Review Board. Evaluations For the preoperative evaluation, the clinicopathological data of the patients were examined. Clinical data in- cluded sex, age, underlying diseases, American Society of Anesthesiologists (ASA) score, BMI, and laboratory tests, including the complete blood cell count, serum chemistry (albumin, creatinine, calcium, and cholester- ol), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and the ABO blood type. A preoperative computed tomography exam was performed to evalu- ate tumor size, tumor location, and distant metastasis. Procedures Partial or radical nephrectomy was performed ac- cording to standard procedures. When preoperative imaging revealed metastasis, nephrectomy and meta- static tumor excision were performed simultaneous- ly in selected patients. Similarly, when an enlarged lymph node was revealed, lymph node dissection was performed. In patients with completely resected me- tastasis and staging greater than T3, immunochemo- therapy or targeted therapy was administered after radical nephrectomy. However, those with inoperable multiple metastases were excluded from the study. Assessments The surgical specimens were evaluated by uropatholo- gists according to the 2010 American Joint Committee on cancer guidelines and the Fuhrman nuclear grading system. Histological subtyping was conducted accord- ing to the 2004 World Health Organization classifica- tion. Postoperative evaluations consisted of a physical examination, laboratory tests, postero-anterior chest radiography, and computed tomography. According to ABO Blood Type in RCC-Ko et al. Table 1. Clinicopathological factors Variables n = 1750 (100%) Sex male/female 1243 (71.0%) / 507 (29.0%) Age 56.0 [IQR 47.0 to 65.0] years BMI 24.20 [22.19 to 26.24] Kg/m2 Tumor diameter 3.65 [IQR, 2.2 to 6.0] cm Pathology Clear cell type 1419 (81.1%) Chromophobe type 155 (8.9%) Papillary type 113 (6.5%) Other 63 (3.2%) Operation Radical/partial 1078 (61.6%)/ 672 (38.4%) Median follow-up duration 35.0 months [IQR 16.0 to 67.0] Recurrence of RCC 271 patients (15.5%) Death of RCC 137 patients (7.8%) Abbreviations: IQR, Interquartile Range. Figure 1. Kaplan-Meier survival analysis. (A) Patients with blood type O showed a significantly longer progression-free survival (PFS) than those with blood type A; however, statistical significance was not reached compared with the results of patients with blood types B and AB. (B) Patients with blood type O showed a longer Cancer-specific survival (CSS) than those with blood type A; however, the difference did not reach statistical significance. pathological stage, these examinations were performed trimonthly or semiannually for the first 2 years and an- nually thereafter. Survival and disease progression data were collected by reviewing medical charts, contacting the family members of patients, or reviewing death cer- tificates. The follow-up duration was from the date of surgery to the last follow-up visit or the date of death. Statistical Analysis SPSS version 19 (SPSS, Inc., Chicago, Illinois, USA) was used for the statistical analysis. The chi-square and Mann-Whitney tests were used to assess the correlation between the ABO blood type and clinicopathological variables. Cancer-specific survival (CSS) and progres- sion-free survival (PFS) among the ABO blood groups were estimated by the Kaplan-Meier method and log- rank test. The Cox proportional hazards regression model was used to identify significant factors related to CSS or PFS. The hazard ratios are presented, along with the 95% confidence intervals. For all tests, alpha Table 2. Relationship between ABO blood type and clinical factors ABO Blood Type Total = n (%) P value O (n = 525, 30.0%) A (n = 568, 32.5%) B (n = 464, 26.5%) AB (n = 193, 11.0%) All (n = 1750, 100%) Age .573b ≤ 46 125 (23.8%) 139 (24.5%) 108 (23.3%) 42 (21.8%) 414 (23.7%) 47-55 145 (27.6%) 138 (24.3%) 113 (24.4%) 46 (23.8%) 442 (25.3%) 56-65 137 (26.1%) 153 (26.9%) 131 (28.2%) 53 (27.5%) 474 (27.1%) > 65 118 (22.5%) 138 (24.3%) 112 (24.1%) 56 (26.9%) 420 (24.0%) Sex .526a Male 375 (71.4%) 408 (71.8%) 318 (68.5%) 142 (73.6%) 1243 (71.0%) Female 150 (28.6%) 160 (28.2%) 146 (31.5%) 51 (26.4%) 507(29.0%) ASA score .531b 1 242 (46.2%) 250 (44.0%) 220 (47.4%) 97 (50.3%) 809 (46.3%) 2 253 (48.3%) 281 (49.5%) 211 (45.5%) 85 (44.0%) 830 (47.5%) 3/4 29 (5.5%) 37 (6.5%) 33 (7.1%) 11 (5.7%) 110 (6.3%) pT stage .971b 1 394 (75.0%) 422 (74.3%) 351 (75.6%) 146 (75.6%) 1313 (75.0%) 2 29 (5.5%) 37 (6.5%) 27 (5.8%) 9 (4.7%) 102 (5.8%) 3 72 (13.7%) 84 (14.8%) 66 (14.2%) 27 (15.0%) 251 (14.3%) 4 30 (5.7%) 25 (4.4%) 20 (4.3%) 9 (4.7%) 84 (4.8%) pN stage .341a Nx/N0 503 (95.8%) 548 (96.5%) 437 (94.2%) 185 (95.9%) 1673 (95.6%) N1 22 (4.2%) 20 (3.5%) 27 (5.8%) 8 (4.2%) 77 (4.4%) pM stage .740a M0 489 (93.1%) 522 (91.9%) 424 (91.4%) 179 (92.7%) 1614 (92.2%) M1 36 (6.9%) 46 (8.1%) 40 (8.6%) 14 (7.3%) 136 (7.8%) Nuclear grade .817a 1/2 285 (54.6%) 298 (52.6%) 249 (54.2%) 99 (51.3%) 931 (53.5%) 3/4 237 (45.4%) 269 (47.4%) 210 (45.8% ) 94 (48.7%) 810 (46.5%) Histology .051a Clear cell 417 (79.4%) 466 (82.0%) 367 (79.1%) 169 (87.6%) 1419 (81.1%) Non clear cell 108 (20.6%) 102 (18.0%) 97 (20.9%) 24 (12.4%) 331 (18.9%) Operation .739a Radical 319 (60.8%) 353 (62.1%) 281 (60.6%) 125 (64.8%) 1078(61.6%) Partial 206 (39.2%) 215 (37.9%) 183 (39.4%) 68 (35.2%) 672 (38.4%) Abbreviations: ASA, American Society of Anesthesiologists. a,Chi-square test; b, Kruskal-Wallis test ABO Blood Type in RCC-Ko et al. Laparoscopic Urology 2767 Vol 13 No 04 July-August 2016 2768 was 0.05, the power was 80%, and P-values were 2-sid- ed, with P < .05 considered statistically significant. RESULTS Clinicopathological data are shown in Table 1. A to- tal of 1243 men (71.0%) and 507 women (29.0%) with RCC who had undergone partial or radical nephrecto- my were enrolled in this study. The median age was 56.0 (interquartile range (IQR) 47.0 to 65.0) years. The median BMI was 24.20 (IQR, 22.19 to 26.24) kg/ m2. The mean ± SD and median tumor diameter were 4.63 ± 3.28 cm and 3.65 (IQR, 2.2 to 6.0) cm, respec- tively. In all, 1313 (75.0%), 102 (5.8%), 251 (14.3%), and 84 (4.8%) patients had pathological tumor stages of pT1, pT2, pT3, and pT4, respectively. Seventy-sev- en patients (4.4%) had pathologically confirmed lo- cal metastatic lymph nodes, and 136 patients (7.8%) had distant metastases. Clear cell type RCC was the most common subtype (1419, 81.1%), followed by the chromophobe type (155, 8.9%). The median fol- low-up duration was 35.0 months (IQR, 16.0–67.0). During the follow-up period, 271 patients experienced RCC recurrence, and 137 patients died from RCC. Among the 1750 patients (Table 2), the most com- mon blood type was A (568, 32.5%), followed by O (525, 30.0%), B (464, 26.5%), and AB (193, 11.0%). The A and AB blood types were more frequent in patients with clear cell type RCC. However, the his- tological subtype was not significantly related to the blood type (P = .051). In general, blood type was not associated with any of the clinicopathological factors. The results of the Kaplan-Meier survival analysis of PFS and CSS according to ABO blood type are shown Table 3. Progression-free survival and Cox regression analysis. Univariate Multivariate HR 95% CI P value HR 95% CI P value Sex (M/F) 0.83 0.63 – 1.09 .181 Age ≤ 46 Reference .001 .258 47-55 1.21 0.83 – 1.77 .330 1.12 0.76 – 1.66 .575 56-65 1.78 1.25 – 2.53 .001 1.42 0.98 – 2.05 .062 > 65 1.85 1.29 – 2.67 .001 1.24 0.84 – 1.81 .281 ASA score 1 Reference < .001 .162 2 1.63 1.25 – 2.12 < .001 1.03 0.78 – 1.37 .813 3/4 3.28 2.20 – 4.89 < .001 1.48 0.97 – 2.26 .071 pT stage T1 Reference < .001 < .001 T2 5.11 3.38 – 7.72 < .001 2.99 1.95 – 4.59 < .001 T3 11.67 8.75 – 15.56 < .001 4.67 3.36 – 6.50 < .001 T4 11.32 7.76 – 16.49 < .001 4.00 2.63 – 6.09 < .001 pN stage 9.69 7.05 – 13.33 < .001 1.14 0.78 – 1.67 .488 pM stage 23.50 18.12 – 30.48 < .001 8.29 6.00 – 11.47 < .001 Nuclear gr. (I-II/III-IV) 4.51 3.39 – 6.01 < .001 1.94 1.42 – 2.64 < .001 Histology (clear / non clear) 1.32 0.95 – 1.84 .102 Operation (radical/partial) 6.51 4.21 – 10.08 < .001 2.34 1.47 – 3.72 < .001 Blood Type O Reference .096 .009 A 1.46 1.07 – 2.00 .018 1.71 1.24 – 2.37 .001 B 1.32 0.95 – 1.85 .102 1.51 1.08 – 2.13 .016 AB 1.48 0.97 – 2.25 .069 1.58 1.03 – 2.43 .037 Abbreviations: ASA, American Society of Anesthesiologists; HR, hazard ratio. ABO Blood Type in RCC-Ko et al. in Figure 1A and 1B, respectively. The 5-year PFS in patients with blood type O was 84.2% (95% CI: 80.3– 88.1, data not shown). Patients with blood type O had a longer PFS than patients with blood type A (P = .017, log-rank test). However, compared with patients with blood types AB and B, the difference did not reach statistical significance (P = .066 and P =.101, respec- tively; log-rank test). The 5-year CSS in patients with blood type O was 91.7% (95% CI: 88.8 – 94.6, data not shown). CSS was longer in patients with blood type O than in those with blood types A, B, and AB, although the difference did not reach statistical significance (P = .062, P =.209, and P = .085, respectively; log-rank test). In the univariate analysis, ABO blood type was a sig- nificant prognostic factor for PFS. Compared with blood type O, blood type A was associated with PFS (95% CI: 1.07–2.00, HR = 1.46, P = .018, respectively; (Table 3). Blood types B and AB were not associat- ed with PFS (95% CI: 0.95–1.85, HR = 1.32, P =.102; 95% CI: 0.97–2.25, HR = 1.48, P = .069, respectively; Table 3). Furthermore, ABO blood type was not relat- ed to CSS (95% CI: 0.98–2.39, HR = 1.53, P = .064; 95% CI: 0.84 – 2.17, HR = 1.35, P = .213; 95% CI: 0.92–2.95, HR = 1.65, P = .091, respectively; Table 4). In the multivariate analysis of PFS, a non-O blood type (A, B, AB) was a significantly stronger prognostic factor for PFS than blood type O (95% CI: 1.24–2.37, HR = 1.71, P = .001; 95% CI: 1.08–2.13, HR = 1.51, P = .016; 95% CI: 1.03–2.43, HR = 1.58, P = .037, re- spectively; Table 3). In the multivariate analysis of CSS (Table 4), blood type A was found to be an independent factor leading to a worse prognosis for CSS (95% CI: 1.05–2.64, HR = 1.66, P = .031, respectively). Howev- er, the results for blood types AB and B did not reach Urological Oncology 2769 Table 4. Cancer-specific survival and Cox regression analysis Univariate Multivariate HR 95% CI P value HR 95% CI P value Sex (M/F) 0.98 0.68 – 1.42 .916 Age ≤ 46 Reference .027 .702 47-55 1.23 0.72 – 2.11 .456 1.28 0.73 – 2.22 .386 56-65 1.95 1.20 – 3.18 .007 1.34 0.80 – 2.26 .267 > 65 1.74 1.04 – 2.93 .037 1.16 0.66 – 2.04 .598 ASA score 1 Reference < .001 .204 2 1.76 1.20 – 2.58 .004 1.15 0.77 – 1.72 .499 3/4 4.06 2.37 – 6.95 < .001 1.68 0.95 – 2.99 .076 pT stage T1 Reference < .001 < .001 T2 7.58 4.00 – 14.35 < .001 3.84 2.00 – 7.35 < .001 T3 17.00 10.57 – 27.32 < .001 4.66 2.76 – 7.86 < .001 T4 24.64 14.42 – 42.12 < .001 6.23 3.46 – 11.20 < .001 pN stage 11.18 7.41 – 16.88 < .001 1.50 0.93 – 2.41 .095 pM stage 27.20 19.22 – 38.50 < .001 8.12 5.33 – 12.37 < .001 Nuclear gr. (I-II/III-IV) 7.14 4.44 – 11.48 < .001 2.58 1.56 – 4.28 < .001 Histology (clear / non clear) 1.07 0.69 – 1.67 .750 Operation (radical/partial) 32.91 8.14 – 133.03 < .001 7.55 1.82 – 31.36 .005 Blood Type O Reference .234 .120 A 1.53 0.98 – 2.39 .064 1.66 1.05 – 2.64 .031 B 1.35 0.84 – 2.17 .213 1.26 0.78 – 2.05 .348 AB 1.65 0.92 – 2.95 .091 1.72 0.95 – 3.14 .075 Abbreviations: ASA, American Society of Anesthesiologists; HR, hazard ratio.. ABO Blood Type in RCC-Ko et al. Vol 13 No 04 July-August 2016 2770 significance (95% CI: 0.95–3.14, HR = 1.72, P = .075; 95% CI: 0.78–2.05, HR = 1.26, P = .348, respectively). DISCUSSION Studies have demonstrated that pathological changes in the ABO antigen are related to RCC. First, ABO anti- gens exist not only on the surface of erythrocytes but also in other body tissues, including the kidney.(15,16) The normal ABO antigen is lost in RCC, and new tumor antigens are acquired.(13,17,18) Thus, a structural change in the ABO antigen occurs in RCC. The altered ABO antigens in RCC are important mediators of membrane signaling and intercellular adhesion.(15,19) It is therefore possible that a specific blood type may enhance dis- ease progression or survival. Second, the deletion of A or B antigens in non-O blood group patients leads to the up-regulation of precursor H and Lewisy ex- pression, both of which stimulate angiogenesis.(20) In addition, non-O blood group patients have higher lev- els of von Willebrand factor and factor VIII.(21) Thus, non-O blood group patients have a greater tendency of hypervascularity and hypercoagulability than blood group O patients, which are typical characteristics of RCC. Third, single nucleotide polymorphism studies evaluating the ABO gene locus have uncovered a re- lationship between the ABO gene and plasma inflam- matory markers, such as tumor necrosis factor alpha. (22) Finally, ABO antigens may be related to systemic inflammation, and chronic inflammation is associated with RCC.(23) In this study, ESR levels were not relat- ed to ABO blood type (Kruskal-Wallis test, P = .352, data not shown), whereas CRP levels were related to ABO blood type (Kruskal-Wallis test, P = .044, data not shown). In particular, patients with blood type O had a lower CRP level than those with a non-O blood type (Mann-Whitney test, P = .007, data not shown). According to the tumor registry of the European Insti- tute of Oncology, the ABO blood type is generally as- sociated with other cancer types. For example, blood type O patients have a significantly lower incidence of pancreatic cancer.(13) Similar results have been reported in other studies. The Prospective Nurses’ Health and Health Professionals Follow-up cohort study revealed that the incidence of RCC is higher in non-O blood type subjects than in blood type O women.(24) A retro- spective study in 900 patients with locoregional RCC reported that blood type O is a significant prognostic factor for overall survival but not a prognostic factor for disease-specific survival, and it is not related to lymph node metastasis.(25) Conversely, Martino et al reported that blood type O is not a prognostic factor for surviv- al. Although blood group O was associated with fewer lymph node metastases, the risk of bilateral RCC was increased.(26) The authors suggested that different inclu- sion criteria, racial variability, and a low event number may have been responsible for the different results in the survival rates between the two reports. In our study, we included both locoregional and advanced cases of RCC. In addition, Korea is a single-race nation. Furthermore, the present study included a relatively larger number of cases and a higher event number than previous studies. Recently, results were published from a large cohort study in Korea that evaluated the prognosis of RCC patients according to ABO blood type.(27) The clini- cal data from our study and a previous study by Lee et al. are very similar. In particular, the distribution of ABO blood type was the same, which could be ex- plained by the single ethnicity of the Korean popula- tion. However, Lee et al. reported that there was no relationship between survival and ABO blood type in patients with RCC. Although both groups conducted large cohort studies, the analysis was retrospective. Our subjects had a higher ASA score and pathological T stage and a short median follow-up duration. Patho- logical M staging also differed slightly between the two groups. These differences may have contributed to the different results reported in these two studies. In this study, differences according to histological sub- type did not reach statistical significance (P = .051, Ta- ble 2). Blood types A and AB were more frequent in pa- tients with clear cell type RCC. However, blood types B and O were more frequent in patients with non-clear cell type RCC, although, in a multivariate analysis, histolog- ical subtype, unlike blood type, was not related to PFS and CSS. To our knowledge, the relationship between histological subtype of RCC and blood type A has not been previously studied. First, the A antigen is locat- ed on chromosome 9, which contains seven exons that span more than 18 kb of genomic DNA, and it may be related to a tumor suppressor gene or oncogene. Second, the A antigen may be related to chronic inflammation or an alteration in the systemic inflammatory reaction.(13,23) For example, a recent study reported that blood type A was related to nasopharyngeal carcinoma and skin cancer.(28,29) Nevertheless, further studies are warranted. The ABO blood type distribution varies widely accord- ing to country, region, and ethnicity.(30) The present data are similar to those reported in Korea (A, 32%; O, 28%; B, 31%; AB, 10%), which is in contrast to the observa- tions that nearly all Bororo and Peruvian Indians have blood type O, eighty-two percent of North American Indians (Blackfoot) have blood type A, and only 9% of Andamanese people have blood type O. However, it is unknown whether CSS or PFS are influenced by the specific blood type. Furthermore, the ABO blood type is inherited and cannot be changed. Regarding this point, our study may be meaningful. Although fre- quent check-ups are helpful to determine disease pro- gression, more studies on single nucleotide polymor- phisms and intracellular signaling of the ABO antigen may be helpful in explaining this genetic variability. Selection bias is one limitation of this retrospective co- hort study. However, efforts were made to minimize the missing values, and we were able to collect a nearly complete dataset. This study also had a prospective com- ponent because the ABO blood type cannot be changed after birth. Thus, the patients in this cohort were auto- matically randomized after birth. Second, because the data were obtained from a single Korean institution, our results cannot be generalized to other populations due to the geographic and ethnicity-related differences in the prevalence of ABO blood types. Our results are, how- ever, similar to those reported in studies from Western countries. To the best of our knowledge, this study is the first to analyze the association between ABO blood type, clinicopathological data, and RCC prognosis in an Asian population. Thus, our study provides a clinical basis upon which further research can be expanded. CONCLUSION The ABO blood type is significantly associated with PFS and CSS in patients with RCC who have under- ABO Blood Type in RCC-Ko et al. gone radical or partial nephrectomy. A non-O blood type (A, B, and AB) was an independent prognostic fac- tor for a worse PFS, and blood type A was an independ- ent factor associated with a worse prognosis for CSS. CONFLICT OF INTEREST There is no conflict of interest REFERENCES 1. Pantuck AJ, Zisman A, Belldegrun AS. The changing natural history of renal cell carcinoma. J Urol. 2001;166:1611-23. 2. Bianchi M, Gandaglia G, Trinh QD, et al. A population-based competing-risks analysis of survival after nephrectomy for renal cell carcinoma. Urol Oncol. 2014;32:46.e1-7. 3. Ferlay J, Soerjomataram I, Dikshit R, Eser S, et al. Cancer incidence and mortality worldwide: Sources, methods and major patterns in GLOBOCAN 2012. Int J cancer. 2015;136:E359-86. 4. Hollingsworth JM, Miller DC, Daignault S, Hollenbeck BK. Five-year survival after surgical treatment for kidney cancer: a population-based competing risk analysis. Cancer. 2007;109:1763-8. 5. Rini BI, Campbell SC, Escudier B. Renal cell carcinoma. Lancet. 2009;373:1119-32. 6. Furniss D, Harnden P, Ali N, et al. Prognostic factors for renal cell carcinoma. Cancer Treat Rev. 2008;34:407-26. 7. Tabibi A, Parvin M, Abdi H, Bashtar, Zamani N, Abadpour B. Correlation Between size of renal cell carcinoma and Its Grade, Stage, and Histological subtype. Urol J. 2007;4:10-3 8. Jeon HG, Jeong IG, Lee JH, et al. Prognostic value of body mass index in Korean patients with renal cell carcinoma. J Urol. 2010;183:448-54. 9. Ko K, Park YH, Lee JW, Ku JH, Kwak C, Kim HH. Influence of nutritional deficiency on prognosis of renal cell carcinoma (RCC). BJU Int. 2013;112:775-80. 10. Aird I, Bentall HH, Roberts JA. A relationship between cancer of stomach and the ABO blood groups. Br Med J. 1953;1:799-801. 11. Costantini M, Fassio T, Canobbio L, Landucci M, Resasco M, Boccardo F. Role of blood groups as prognostic factors in primary breast cancer. Oncology. 1990;47:308-12. 12. Miyake M, Taki T, Hitomi S, Hakomori S. Correlation of expression of H/Le(y)/ Le(b) antigens with survival in patients with carcinoma of the lung. N Engl J Med. 1992;327:14-8. 13. Iodice S, Maisonneuve P, Botteri E, Sandri MT, Lowenfels AB. ABO blood group and cancer. Eur J Cancer. 2010;46:3345-50. 14. Yuzhalin AE, Kutikhin AG. ABO and Rh blood groups in relation to ovarian, endometrial and cervical cancer risk among the population of South-East Siberia. Asian Pac J Cancer Prev. 2012;13:5091-6. 15. Hakomori S. Antigen structure and genetic basis of histo-blood groups A, B and O: their changes associated with human cancer. Biochim Biophys Acta. 1999;1473:247-66. 16. Dabelsteen E, Gao S. ABO blood-group antigens in oral cancer. J Dent Res. 2005;84:21-8. 17. Ghazizadeh M, Kagawa S, Kurokawa K. Immunohistochemical studies of human renal cell carcinomas for ABO(H) blood group antigens, T antigen-like substance and carcinoembryonic antigen. J Urol. 1985;133:762-6. 18. Cordon-Cardo C, Reuter VE, Finstad CL, et al. Blood group-related antigens in human kidney: modulation of Lewis determinants in renal cell carcinoma. Cancer Res. 1989;49:212-8. 19. Wolpin BM, Chan AT, Hartge P, et al. ABO blood group and the risk of pancreatic cancer. J Natl Cancer Inst. 2009;101:424-31. 20. Halloran MM, Carley WW, Polverini PJ, et al. Ley/H: an endothelial-selective, cytokine- inducible, angiogenic mediator. J Immunol. 2000;164:4868-77. 21. Tirado I, Mateo J, Soria JM, et al. The ABO blood group genotype and factor VIII levels as independent risk factors for venous thromboembolism. Thromb Haemost. 2005;93:468-74. 22. Harrison ML, Obermueller E, Maisey NR, et al. Tumor necrosis factor alpha as a new target for renal cell carcinoma: two sequential phase II trials of infliximab at standard and high dose. J Clin Oncol. 2007;25:4542-9. 23. Soyupek S, Tulunay O, Armagan A, Hoscan B, Perk H. Clinical importance of intratumoral and normal renal parenchymal inflammatory cell infiltration in renal cell carcinoma. Scand J Urol Nephrol. 2007;41:387-91. 24. Joh HK, Cho E, Choueiri TK. ABO blood group and risk of renal cell cancer. Cancer Epidemiol. 2012;36:528-32. 25. Kaffenberger SD, Morgan TM, Stratton KL, et al. ABO blood group is a predictor of survival in patients undergoing surgery for renal cell carcinoma. BJU Int. 2012;110:E641-6. 26. de Martino M, Waldert M, Haitel A, Schatzl G, Shariat SF, Klatte T. Evaluation of ABO blood group as a prognostic marker in renal cell carcinoma (RCC). BJU Int. 2014;113:E62-6. 27. Lee C, You D, Sohn M, et al. Prognostic value of ABO blood group in patients with renal cell carcinoma: single-institution results from a large cohort. J Cancer Res Clin Oncol. 2015;141:1441-7 28. Ouyang PY, Su Z, Mao YP, Liu Q, Xie FY. Prognostic value of ABO blood group in southern Chinese patients with established nasopharyngeal carcinoma. Br J Cancer. 2013;109:2462-6. ABO Blood Type in RCC-Ko et al. Laparoscopic Urology 2771 Vol 13 No 04 July-August 2016 2772 29. Cihan YB, Baykan H, Kavuncuoglu E, et al. Relationships between skin cancers and blood groups--link between non-melanomas and ABO/Rh factors. Asian Pac J Cancer Prev. 2013;14:4199-203. 30. bloodbook web site http://www.bloodbook.com/ world-abo.html. ABO Blood Type in RCC-Ko et al.