[Correlation of the expression of A, B isoantigens with its precursor H antigen in transitional cell carcinoma and the clinical signification of the expression]

The expression of ABO (H) isoantigens in tumors from 96 patients with transitional cell carcinomas (TCC) and the precursor H antigen of A or B antigens were studied by using immunohistochemical technique (ABC method). In our series ABO(H)isoantigens were demonstrated in 57 of 96(59.4%), grade I 76.5%, II 69.4% and III 33.3% respectively. The deletion of ABO(H) isoantigens was related statistically with the histologic grade of TCC (P less than 0.01) and the recurrence of the tumors (P less than 0.05). The results showed that the expression of the precursor H substance was very well related with the expression of A or B isoantigen (r = 0.99, P less than 0.001). The deletion of precursor H substance could more reliably predict the clinical course of the subsequent recurrence and mortality in A, B or AB type blood patients with TCC than that of A or B isoantigen. Detecting H substance can substitute completely detecting A or B isoantigen in tumors of A, B or AB type blood patients, and has more practical value clinically.

Reduction of major histocompatibility complex class I antigens on invasive and high-grade transitional cell carcinoma

We examined immunohistologically the expression of major histocompatibility complex (MHC) class I and II antigens, which play important roles in immune reactions, on transitional cell carcinoma (TCC). When stained with monoclonal antibody W6/32 against class I antigens, reduced staining was observed in 34 of 46 TCCs and was virtually absent in 15 of these. The cases showing reduced staining were much more frequent (29 of 34) in high- to moderate-grade than in low-grade TCC. Furthermore, class I antigens were reduced in 18 of 19 invasive TCCs, but in 16 of 27 superficial TCCs. Thus, the reduction of class I antigens was correlated significantly with a decreased degree of tumour cell differentiation and the presence of invasion. Class II antigens on TCC showed variable expression and were not related to tumour grade or stage.

Selective and non-selective loss of immunoregulatory molecules (HLA-A,B,C antigens and LFA-3) in transitional cell carcinoma

The expression of the major histocompatibility complex (MHC) class I and II antigens and lymphocyte function-associated antigen-3 (LFA-3) was investigated using immunohistochemical staining of bladder tissue sections from 18 patients with transitional cell carcinoma (TCC) and two normal bladder specimens. The expressions of HLA-A,B,C antigens varied greatly between different tumours. Complete loss was observed in one of 18 cases. Moderate to strong expression of HLA-A,B,C antigens was observed in 10 of 18 cases with the remaining seven cases showing either weak expression or expression on only a proportion of the tumour cells. Selective loss of HLA-Bw6 was seen in one of 18 cases. In many cases heterogenous and often focal expression of HLA-D products was seen. In one case tumour cells not expressing HLA-DR antigens were adjacent to strongly HLA-DR expressing non-neoplastic bladder epithelium, indicating a lack of inducible HLA-DR in the tumour cells. LFA-3 was undetectable in two of 18 cases with the remaining 16 cases showing moderate to strong expression of the molecule. These findings indicate that a substantial proportion of bladder tumours have one or more of a wide range of different alterations in the expressions of immunoregulatory molecules that could contribute to escape from immune surveillance.

[Production of monoclonal antibodies against human bladder cancer cells and application to immunohistochemical analysis of bladder cancer]

Two hybridomas secreting two monoclonal antibodies IgG1 B1.4 and IgG2a B1.6 were obtained by immunizing BALB/c mice with human bladder cancer cell line EJ-1. In immunohistochemical staining of cryopreserved tissues, B1.4 reacted with 0 of 9 grade 1 TCC, 6 of 11 grade 2, all of 6 grade 3 and five metastatic specimens. The antigen recognized by B1.4 was not expressed by normal urothelial cells but were expressed by vascular endothelial cells and muscle of tunica media. The target antigen of B1.6 was expressed by normal urothelial cells and all grade of TCC. In this study, it was demonstrated that poorly differentiated bladder cancer and metastatic specimens of bladder cancer express a vascular carbohydrate antigen. Taking the escape mechanism of immune surveillance, into consideration, it is possible that the antigen recognized by B1.4 is an indicator of metastatic potential of bladder cancer.

Bacillus Calmette-Guérin-treated superficial bladder cancer: correlation of morphology with immunophenotyping

Thirty-five biopsies from 19 patients with superficial transitional cell carcinoma of the bladder, treated with intravesical bacillus Calmette-Guérin (BCG), were assessed histologically and immunohistochemically. Pretreatment biopsies were available for comparison in all cases and five cases of non-specific cystitis were also examined. The inflammatory infiltrate was assessed with a streptavidin-biotin-peroxidase method using UCHL1, MT1, LN3, L26, HAM56, MAC387, Leu7 and anti-S100 in paraffin sections, and in 18 specimens were frozen tissues were available, Leu1, 2, 3, 4, 14, OKT10, HLA-DR and anti-Tac antibodies were applied. Post-treatment bladder biopsies showed severe oedema and a variable degree of inflammation. A granulomatous inflammation was seen in 11 cases, with granulomas present in six prostatic biopsies and acid-fast bacilli in two cases. The lymphoid infiltrate in all biopsies were largely T lymphocytes with a predominance of T helper cells present, often as a band-like infiltrate pressing against the residual epithelium, or the denuded bladder surface, and distributed in the vicinity of the granulomas. Activated lymphocytes were prominent in seven cases, although a moderate infiltrate of such cells was seen in all instances. Tac antigen was only occasionally expressed, and in a few NK cells were present among the infiltrates. In eight cases, HLA-DR was expressed in epithelial cells following BCG treatment, whereas all pre-treatment epithelial were negative.

Tumour-induced host stromal-cell transformation: induction of mouse spindle-cell fibrosarcoma not mediated by gene transfer

Tumour-induced host-cell transformation has been addressed by examining human tumours in situ and following xenograft to nude mice. We have found evidence for the transformation of host stromal fibroblasts both in vivo and following the introduction of the tumours to in vitro culture. The in vitro culture of one such xenograft--derived from a human prostatic adenocarcinoma--resulted in the outgrowth of a transformed aneuploid mouse cell line. This transformed line was tumourigenic both in BALB/c nu/nu (nude) mice and in heterozygous nu/+mice, with the morphology of a spindle-cell sarcoma. The cell line did not express human isozymes or human histocompatibility antigens, nor were human chromosomes present. Moreover, human DNA sequences were not detected by human Alu repeat sequence element probing in the transformed cell line grown either in vitro or in vivo. The line contained retroviral long terminal repeat sequences but there was no evidence of proviral activation. These findings indicate that tumour cells may cause transformation of neighbouring stromal cells; that this transformation may proceed in the absence of DNA transfer or activation of endogenous proviruses; and that the means of this observed transformation may involve humoral factors elaborated by the tumour cells.

Urinary cytokines following photodynamic therapy for bladder cancer. A preliminary report

This preliminary study was undertaken to test for the presence of urinary cytokines whose detection would provide evidence in support of the theory that photodynamic therapy (PDT) produces an immunologic response in patients treated for bladder cancer. Gamma interferon, interleukin 1-beta, interleukin 2, and tumor necrosis factor-alpha were assayed for in the urine of 4 patients treated with photodynamic therapy for bladder cancer, in 7 control patients undergoing transurethral surgical procedures, and in 5 healthy control subjects. Quantifiable concentrations of all cytokines, except gamma interferon, were measured in urine samples from the PDT patients with the highest light energies, while no urinary cytokines were found in the PDT patient who received the lowest light energy nor in any of the control subjects. These findings suggest that a local immunologic response may occur following PDT for bladder cancer.

[A transitional cell carcinoma of the urinary bladder with a high level of serum CA 19-9--a case report]

Reported is the case of a 72 year-old man who was hospitalized because of abdominal pain and gross hematuria. A subsequent laboratory examinations revealed a high level of serum CA 19-9, and abdominal computed tomography showed a mass lesion behind the urinary bladder and multiple lymphadenopathy. Examination of the digestive organs revealed no abnormality, however cystoscopy showed a submucosal a tumor with a partly ruddy surface. Thus, a percutaneous needle biopsy and a transurethral biopsy were performed. The pathological findings indicated a transitional cell carcinoma of the urinary bladder, and ABC-peroxidase staining revealed the presence of CA 19-9 positive cells in a portion of the carcinomatous cells.

Effects of local bacillus Calmette-Guerin therapy in patients with bladder carcinoma on immunocompetent cells of the bladder wall

The antitumoral effects of intravesical bacillus Calmette-Guerin against recurrent superficial urothelial bladder cancer seem to be linked to immunological effector mechanisms. To characterize further the local cellular response in the bladder wall of patients receiving intravesical bacillus Calmette-Guerin bladder biopsies were examined before and immediately after a 6-week course of bacillus Calmette-Guerin and for up to 1 year at 3-month intervals thereafter. The results showed a marked infiltration after bacillus Calmette-Guerin therapy predominantly of the suburothelial tissue with mononuclear cells, which expressed activation markers and accumulated to follicle-like granulomatous structures. With regard to T lymphocyte subsets the ratio of T helper-to-T suppressor cells in the bladder wall increased from 0.5 to nearly 2. This phenomenon persisted even in biopsies 1 year after initial treatment. In some probes activated mononuclear cells invaded the urothelium, emanating from suburothelial granulomas. It is tempting to assume that these changes within the local immunocompetent cells are related to the therapeutic effect of bacillus Calmette-Guerin against bladder cancer.

Immunohistochemical and immunocytochemical study of bladder carcinomas using the epithelium-specific, tumour-associated monoclonal antibodies HMFG1 and AUA1

The antigenic expression of normal bladder epithelium and transitional carcinomas has been studied using the epithelium-specific, tumour-associated monoclonal antibodies HMFG1 and AUA1. Tissues from 79 cases of bladder carcinoma and 11 cases of non-neoplastic bladder tissues were stained with both the haematoxylin-eosin (H/E) and the indirect two-stage immunoperoxidase methods using the monoclonal antibodies (MAbs) HMFG1 and AUA1 at a concentration of 25 micrograms ml-1. Positive and negative controls were also used. Moreover, 46 urine smears prepared after cytocentrifugation were stained with both the Papanicolaou and the indirect two-stage immunoperoxidase methods. The results showed that HMFG1 reacted with the majority of cases of grade III carcinomas and carcinomas in situ and with a subset only of low-grade (I and II) carcinomas. The pattern of staining showed the following characteristics: (1) the epithelial surface membrane stained both in normal bladder and bladder carcinomas (surface of the papillae), (2) a variant number of cancer cells, increasing with the degree of malignancy, showed membrane and/or cytoplasmic staining, (3) tumours of the same histological grade showed antigenic heterogeneity. The MAb AUA1 was not widely expressed. The immunocytochemical study confirmed the reaction of HMFG1 with a variant number of malignant urothelial cells exfoliated in urine. Their reaction with AUA1 was much more limited. The immunocytochemical staining seemed to be more sensitive in the detection of malignant cells in some cases which had been characterized as negative or suspicious for malignancy by the Papanicolaou examination. The intravesical treatment with chemotherapeutic agents did not seem to influence the antigenic expression of malignant urothelial cells.

Expression of CD15 antigen in urinary bladder transitional cell carcinoma

The biopsy specimens of 91 patients between the ages of 38 and 94 with transitional cell carcinoma of the bladder were retrospectively reviewed to determine if the expression of CD15 antigen detected by a monoclonal antibody MC2 was correlated with prognosis. Expression was variable, ranging from strong expression of the antigen by only the superficial cells in well differentiated papillary lesions to weak expression by most cells in solid or invasive tumours. In the invasive component there was a correlation between MC2 expression and tumour type, suggesting that the cell surface carbohydrate detected by MC2 may have a role in cell adhesion. There was no correlation between staining and survival. It is concluded that tumour type, grade, and stage remain the best prognostic indicators of urothelial tumours.

Elevations of cytokines interleukin-1, interleukin-2 and tumor necrosis factor in the urine of patients after intravesical bacillus Calmette-Guerin immunotherapy

In an attempt to elucidate further the immunological mechanisms responsible for the effectiveness of intravesical bacillus Calmette-Guerin in the therapy of superficial urothelial bladder cancer, a prospective study was performed in which the urine of patients was examined before and after 6 intravesical instillations of bacillus Calmette-Guerin for the presence of the cytokines interleukin-1, interleukin-2 and tumor necrosis factor-alpha. Biological assays such as specific sandwich enzyme-linked immunosorbent assays were used for the analysis of each cytokine. Urinary titers of interleukin-1, interleukin-2 and tumor necrosis factor increased significantly after bacillus Calmette-Guerin instillation but showed inter-individual differences. The maximum of secretion into the urine was seen between 4 and 8 hours after the instillation, and titers returned to baseline values within 24 hours. The differences in 24-hour secretion between the bacillus Calmette-Guerin-treated (10 patients) and the control (10) groups were significant with respect to all cytokines as tested in both assays each, except for the interleukin-1 biological assay. These results reflect the strong inflammatory response in the bladder wall to bacillus Calmette-Guerin, in which the urinary secretion of the detected cytokines may be associated with the local tumor control.

[Study of a monoclonal antibody against new epithelial membrane antigens of transitional cell carcinoma]

Immunizing mice with a transitional cell cancer (TCC) tissue in the renal pelvis, we produced a monoclonal antibody (EH14) against new epithelial antigens. After the mice were immunized repeatedly, their splenic cells were harvested and fused with NS/1 myeloma cells. The normal kidney tissue of the same patient was used on Dot blots to select the hybridoma. A a result, one hybridoma whose antibody (EH14) reacted very strongly with TCC but only faintly with normal kidney tissue or normal bladder mucosa was obtained. On immunohistochemistry, EH14 stained all of the 29 TCC tissues. EH14 also stained uterus cancer (7/7) and gastric cancer (6/6) as well as the normal squamous cell and many types of the normal epithelium. All of the lymphnodes containing metastatic bladder cancer were strongly stained with EH14. EH14, however, did not stain interstitial tissues, muscles and sarcomas. The molecular weight of the antigen recognized by EH14 was 14KD and 28 KD on Western blot analysis, and the antigen was stable with formalin or ethanol. The antigen was not the same as that reported previously, and may be useful as a histological marker of TCC.

Clinical studies on cell-mediated immunity in patients with urinary bladder carcinoma: blastogenic response, interleukin-2 production and interferon-gamma production of lymphocytes

Patients with advanced malignant neoplasms have a variety of abnormal lymphocyte functions. We examined the PHA blastogenic response, interleukin-2 (IL-2) production and interferon-gamma (IFN-gamma) production of lymphocytes in 39 bladder cancer patients and 20 control subjects. Correlation between these parameters was also studied. IL-2 production was measured by 3H-thymidine-labelled CTLL-2 assay, and IFN-gamma production was measured by immunoradiometric assay using 2 mouse monoclonal antibodies. As a result, in high stage bladder cancer patients, the PHA blastogenic response, IL-2 production and IFN-gamma production were impaired. However, these parameters were not significantly different between low stage bladder cancer patients and control subjects. There was a significant correlation between the PHA blastogenic response and IL-2 production but no significant correlation between the PHA blastogenic response and IFN-gamma production.

Clinical studies on bladder tumor-associated antigen in serum of patients with bladder cancer by using monoclonal antibody and sandwich ELISA

Investigations on tumor-associated antigen in the serum of patients with bladder cancer by using monoclonal antibody Hb 7A and sandwich ELISA were carried out on 36 patients with bladder cancer (BCa group), 18 patients with other tissue tumor (OTT group) and 22 normal subjects (control group). The average OD value of Hb 7A antigen of BCa group, OTT group and control group was 0.315 +/- 0.033, 0.124 +/- 0.026 and 0.12 +/- 0.021 respectively. The OD value of Hb 7A antigen in BCa group was significantly higher than that of control group and of OTT group (P less than 0.01), but there was no obvious difference between the control group and OTT group (P greater than 0.05). The positive detection rate in BCa group was 86% (31/36), while detection in all 22 normal subjects and the 18 patients of OTT group yielded negative results. The results indicated that the method of using McAb Hb 7A and sandwich ELISA, characterized by high specificity and sensitivity, is of value for clinical diagnosis and follow-up of patients with bladder cancer and general survey of persons at high risk of bladder cancer.

Flow cytometric evaluation of Thomsen-Friedenreich antigen on transitional cell cancer using monoclonal antibody

In 31 transitional cell cancer (TCC) tissues and 5 normal bladder mucosae (NBM), we compared the results of flow cytometry (FCM) and immunohistochemical examination in evaluating the expression of Thomsen-Friedenreich antigen (T-Ag) using a monoclonal antibody. On immunohistochemical examination, 14 (45%) cancer tissues showed T-Ag, while 7 (23%) cancer tissues and all NBM showed only cryptic T-Ag, which was detected only after neuraminidase treatment. Ten (32%) high grade cancer tissues showed neither T-Ag nor cryptic T-Ag. ON FCM the T-Ag positive cells (TPC) and the T-Ag positive cells after neuraminidase treatment (nTPC) were counted in fresh cell suspensions. FCM was more sensitive than immunohistochemical study in detecting T-Ag. Additionally, FCM revealed that some tumors had both T-Ag and cryptic T-Ag at the same time. The ratio of nTPC to TPC was well correlated with the stage or grade of the tumor and may be a more reliable marker of TCC than the expression of T-Ag assessed by immunohistochemical techniques.

Defective interleukin-1 production of monocytes in patients with bladder cancer

Patients with advanced malignant neoplasms have a variety of abnormal lymphocyte and monocyte functions. We examined the PHA (phytohaemagglutinin) blastogenic response of lymphocytes and interleukin-1 (IL-1) production of monocytes in 40 bladder cancer patients and 16 control subjects. The correlation between the 2 parameters was also studied. The PHA blastogenic response was measured by the incorporation of 3H-thymidine into lymphocytes. IL-1 production was assayed by the murine thymocyte 3H-thymidine incorporation assay. As a result, the PHA blastogenic response and IL-1 production were significantly lower in the high stage bladder cancer patients compared to the control subjects and low stage patients. However, there was no significant correlation between the 2 parameters. Furthermore, with the addition of indomethacin, IL-1 production in the control subjects and low stage patients improved to the same degree, but it did not reach the control level in the high stage patients.

[Prostate specific monoclonal antibody gained by glycolipid immunization]

Extraction of glycolipid component from hypertrophic and cancerous prostatic tissue were performed using chloroform-methanol solution and isopropanol-hexan-solution. The extract was separated into the "upper phase" and "lower phase" by Folchs fractionation technic. Each fraction was conjugated with acid treated salmonella minesota and than it was injected subcutaneously, intra-peritoneally and finally intravenously to BALB/c mice. Spleen cells from immunized mice were fused with P3X63, and antibody APG1 was obtained. APG1 shows a preferential reactivity towards prostatic tissue by the immunohistochemical analysis. Furthermore, the immunohistochemical analysis using enzyme and acid treated tissue and TLC immunostaining indicate that this monoclonal antibody specifically recognizes the sialylglycochain expressed in the prostatic tissue.

Clinical significance of natural killer activity in patients with transitional cell carcinoma of the bladder

We studied the relationship of natural killer activity from peripheral blood mononuclear cells with clinical stage of disease and the different modalities of treatment in 67 untreated patients with transitional cell carcinoma of the bladder and 29 normal controls. Peripheral blood mononuclear cells from 39 patients with superficial bladder tumor (stages Ta and T1) showed a natural killer cell activity similar to that of controls (p greater than 0.05), while in 28 patients with infiltrating tumors (stages T2, T3 and T4) this activity was significantly depressed (p less than 0.01). This functional phenomenon cannot be ascribed to a deficient number of natural killer cells in patients with infiltrating tumors, since the amounts of HNK-1+ (Leu 7), CD16+ (Leu 11) and CD11b+ (OKM1) cells in peripheral blood mononuclear cells were similar in the 3 groups of subjects (p greater than 0.05). Furthermore, the natural killer activity of peripheral blood mononuclear cells was normal (p greater than 0.05) in patients who underwent transurethral resection of the tumors and intracavitary cytostatic therapy with doxorubicin who remained free of disease at least 6 months after treatment. However, in patients with superficial recurrent tumor a significant decrease in the natural killer activity of peripheral blood mononuclear cells was observed (p less than 0.05), which was more pronounced in those with infiltrating recurrence. Also, in the latter patients total cystoprostatectomy was associated with a relevant increase in the spontaneous level of peripheral blood mononuclear cells. We conclude that in patients with transitional cell carcinoma of the bladder there is a correlation of the levels of natural killer activity in peripheral blood mononuclear cells with clinical evolution and pathological stage of disease. The determination of this activity is useful to monitor patients with transitional cell carcinoma of the bladder.

HLA antigens and transitional cell carcinoma of the bladder

A possible association between HLA antigens and transitional cell carcinoma of the bladder was searched for in 56 patients and 200 healthy kidney donors. Statistical analysis showed that HLA antigens A23, A25, A28, BW4, BW21, BW22 and CW4 are more common in bladder tumor patients, whereas B27 and BW6 were more common in the control group. The relative risk for HLA CW4 was 2.07 (95% confidence interval 1.51-2.48). Except for CW4, these findings are inconsistent with previous reports. We believe this to be due to various misleading factors, and thus not conclusive. Even if such a statistical association exists, this appears to be clinically not relevant and, therefore, should not alter standard practice.

Comparison of T suppressor factors from tumour-bearing mice and mice immunized with a monoclonal anti-idiotypic antibody

Certain dosage schedules of a monoclonal anti-idiotypic antibody (related to a murine bladder carcinoma) were found to induce suppressor factor production by syngeneic mice. This suppressor factor resembled the factor from tumour-bearing mice with respect to idiotype specificity, possession of molecular markers (reactive with anti-IJ and B16G antibodies) and production by Lyt2+IJ+ T cells in spleen cell cultures. The two factors differed with respect to Igh restriction in an in vitro assay (leucocyte adherence inhibition) and ability to suppress the induction of delayed-type hypersensitivity to tumour antigen.

Urine-TPA (tissue polypeptide antigen), flow cytometry and cytology as markers for tumor invasiveness in urinary bladder carcinoma

Urine-Tissue Polypeptide Antigen (U-TPA) was measured in 81 patients with a previously diagnosed bladder carcinoma. U-TPA was elevated in 74% of the patients with invasive bladder cancer as compared to only 15% of the patients with superficial tumors. Only one patient without a tumor recurrence had an elevated U-TPA level (4%). The results were compared with cytological grading and flow-DNA measurements in a multivariate analysis with T-category as the result variable. U-TPA and grade showed each, independently, a significant relation (P much less than 0.001) to T-category whereas the result of the DNA measurements did not explain the variation in T-category when U-TPA and grade were already in the equation. For diagnostic purposes U-TPA seems to be of limited value but may serve as an indicator of tumor recurrence in bladder cancer patients.

Combination of blood group ABH antigen status and DNA ploidy as independent prognostic factor in transitional cell carcinoma of the urinary bladder

The prognostic value of DNA ploidy and blood group (ABH) antigen reactivity was studied in a consecutive retrospective study of 230 patients with primary transitional cell carcinoma of the urinary bladder. In 195 cases the DNA ploidy and ABH reactivity could be assessed in paraffin-embedded tissue. Early progression (in the first 3 years) occurred in 2% of the patients with diploid ABH positive tumours and in 31% of those with aneuploid ABH negative tumours. The 5-year survival rates corrected for intercurrent mortality were 95 and 56% respectively. In a Cox multivariate analysis, T category, age at diagnosis and histological grade emerged as significant independent prognostic indicators of bladder cancer death, whereas ABH reactivity and DNA ploidy had no significant independent value. However, if the combination of ABH reactivity and DNA ploidy was included in the Cox model, this and T category were independent predictors. When this Cox model was applied to assess the risk of progression, the only independent prognostic factor was the combination of ABH reactivity and DNA ploidy.

Heterogeneic expression of blood group A and H isoantigens in bladder tumors: association with nuclear volume

Intratumor heterogeneity is a major problem in immunodiagnosis and treatment of carcinomas. To elucidate the well-known heterogeneity in transitional-cell carcinomas of the ability to express blood group ABO isoantigens, a stereological estimate of the mean nuclear volume in areas expressing blood group antigens was compared to the estimate from areas of identical pathological grade at which antigen expression was deleted. Four microscopic fields were examined from antigen-positive and four from antigen-negative areas in sections from 21 blood group O and 20 blood group A individuals. The sections were stained before examination by an indirect peroxidase method using monoclonal anti-H and anti-A antibodies. The mean nuclear volume increased, as expected, with increasing pathological grade. In blood group O individuals the mean nuclear volume was 241.5 microns 3 in antigen-positive areas and 338.2 microns 3 in antigen-negative areas (2p less than 0.0005) of identical pathological grade. In group A individuals the mean nuclear volume was 217.1 microns 3 in positive areas and 351.1 microns 3 in corresponding negative areas (2p less than 0.0025). The variation in volume parameter was essentially caused by a true variation between tumors (greater than 82%). The results indicate a complex biological mechanism associated with the cellular ability to express blood group antigens.