Radical therapy for muscle-infiltrating bladder cancer (cystectomy or radiotherapy): does age affect the final therapeutic benefit for the patient?

PURPOSE: To evaluate the therapeutic outcome of radical cystectomy and radical radiotherapy in patients with T2N0M0 clinical stage bladder cancer in relation to their age. PATIENTS AND METHODS: Between 1995-2006, 119 patients with clinical stage T2N0M0 bladder cancer were treated with radical radiotherapy (group A) and were divided in 2 subgroups: >70 years old (A1) and 70 years old/B1 subgroup and

Thrombospondin-1 expression in urothelial carcinoma: prognostic significance and association with p53 alterations, tumour angiogenesis and extracellular matrix components.

BACKGROUND: Thrombospondin-1 (TSP-1) is an extracellular matrix component glycoprotein, which is known to be a potent inhibitor of angiogenesis and may be important in cancer invasiveness. We examined the TSP-1 expression in correlation with conventional clinicopathological parameters to clarify its prognostic significance in bladder cancer. In addition, the possible correlation of TSP-1 expression with microvessel count, VEGF expression, p53 expression as well as with the expression of the extracellular matrix components was studied to explore its implication in vascularization and tumour stroma remodeling. METHODS: The immunohistochemical expression of TSP-1 in tumour cells and in the tumour stroma was studied in 148 formalin-fixed paraffin-embedded urothelial cell carcinoma tissue samples. RESULTS: TSP-1 was detected in perivascular tissue, at the epithelial-stromal junction, in the stroma and in tumour cells in the majority of the cases. In tumour cells, low TSP-1 expression was observed in 43% of the cases, moderate and high in 7%, while 50% showed absence of TSP expression. A higher TSP-1 immunoreactivity in well and moderately differentiated tumours compared to poorly differentiated was noted. PT1 tumours showed decreased TSP-1 expression in comparison to pTa and pT2-4 tumours. Increased tumour cell TSP-1 expression was related to increased microvessel density. In the tumour stroma, 37% of the cases showed small amount of TSP-1 expression, 7.5% moderate and high, while 55% of the cases showed absence of TSP-1 stromal immunoreactivity. Stromal TSP-1 expression was inversely correlated with tumour stage and tumour size. This expression was also positively correlated with microvessel density, VEGF expression and extracellular matrix components tenascin and fibronectin. Using univariate and multivariate analysis we didn't find any significant correlation of TSP-1 expression in superficial tumours in both tumour cells and tumour stroma in terns of the risk of recurrence and disease progression CONCLUSION: Our data suggest that both tumour and stromal TSP-1 expression may play a role in tumour aggressiveness and angiogenesis. In addition, the correlation of stromal TSP-1 expression with extracellular matrix components fibronectin and tenascin indicate its possible implication in tumour stroma remodeling.

Hypericum perforatum L. extract - novel photosensitizer against human bladder cancer cells.

The polar methanolic fraction (PMF) of the Hypericum perforatum L. extract has recently been developed and tested as a novel, natural photosensitizer for use in the photodynamic therapy (PDT), and photodynamic diagnosis (PDD). PMF has been tested on HL-60 leukemic cells and cord blood hemopoietic progenitors. In the present study, the efficacy of PMF as a phototoxic agent against urinary bladder carcinoma has been studied using the T24 (high grade metastatic cancer), and RT4 (primary low grade papillary transitional cell carcinoma) human bladder cancer cells. Following cell culture incubation, PMF was excited using 630 nm laser light. The photosensitizer exhibited significant photocytotoxicity in both cell lines at a concentration of 60microg/ml, with 4-8 J/cm(2) light dose, resulting in cell destruction from 80% to 86%. At the concentration of 20microg/ml PMF was not active in either cell line. These results were compared with the results obtained in the same cell lines, under the same conditions with a clinically approved photosensitizer, Photofrin. Photofrin was used in the maximum clinically tolerable dose of 4microg/ml, and it was also excited with 630 nm laser light. In the T24 cell Photofrin exhibited slightly less photocytotocixity, compared with PMF, resulting in 77% cell death with 8J/cm(2) light dose. However, against the RT4 cells Photofrin resulted in minimal cell death (9%) with even 8J/cm(2) light dose. Finally, the type of cell death induced by PMF photoactivation was studied using flow cytometry and DNA laddering. Cell death by PMF photodynamic action in these two bladder cell lines is caused predominently by apoptosis. The reported significant photocytotoxicity, selective localization, natural abundance, easy, and inexpensive preparation, underscore that the PMF extract hold the promise of being a novel, effective PDT photosensitizer.

Prognostic significance of thymidine phosphorylase in superficial bladder carcinoma.

OBJECTIVE: We investigated the expression of thymidine phosphorylase (TP) in bladder carcinomas and assessed its prognostic significance in superficial bladder cancer samples. PATIENTS AND METHODS: We studied 142 primary bladder cancer samples immunohistochemically for nuclear thymidine phosphorylase (TPN), cytoplasmic (TPC) and stromal (TPSTR) expression. We correlated them with standard clinicopathological features (grade, stage, concurrent in situ, multiplicity, primary or recurrent status), as well with recurrence and progression. We examined also the relationship between TP and tumor microvessel density. RESULTS: The level of all types of TP correlated well with stage, while grade correlated well only with TPSTR and the presence of carcinoma in situ only with TPN. Patients with low levels of TPN had a longer tumor free interval, during a 38.6 months mean follow up time. Regarding the association between TP count and microvessel density we found the strongest association with TPSTR (p=0.003), a borderline statistical significance with TPC (p=0.049) and no relationship with TPN (p=0.072). CONCLUSIONS: We suggest that the assessment of TPN might be useful for predicting recurrence in superficial bladder cancer. We propose also that TP may stimulate angiogenesis.

Immunohistochemical expression of retinoblastoma gene product (Rb), p53 protein, MDM2, c-erbB-2, HLA-DR and proliferation indices in human urinary bladder carcinoma.

Archival biopsy specimens from transitional cell bladder cancers (n=88) were analysed immunohistochemically for the expression of the retinoblastoma (Rb) gene protein, p53, mdm2, c-erbB-2, HLA-DR antigen and proliferation indices. An altered nuclear expression of Rb, p53 and mdm2 was observed in 55.2%, 33.3% and 18.2% of tumors respectively. Cytoplasmic membrane immunoreactivity (>25% tumor cells) for c-erbB-2 was detected in 14.1% of tumors and aberrant HLA-DR antigen cytoplasmic staining (>5% of tumor cells) in 22.2% of the cases. P53 overexpression was associated with higher tumor grade and stage. Aberrant HLA-DR antigen expression and PCNA were also correlated with the grade of differentiation and tumor stage. MIB1 was statistically correlated with stage. pRb scores and HLA-DR antigen expression were correlated with proliferation activity as determined by PCNA and MIB1 immunostaining. p53 protein was also strongly correlated with the proliferation index PCNA. A strong correlation between PCNA and MIB1 (p<0.0001) was also found. In addition a statistically positive correlation between p53 and HLA-DR antigen expression was observed. Our data show that, although pRb and p53 protein expressions are not associated between them, they may contribute to the growth fraction of the bladder cancer. In addition, p53 and HLA-DR antigen expression could be indicators of aggressive behavior of bladder cancer.

Lymphocyte subsets in superficial bladder cancer: correlation with biological activity of the tumours.

BACKGROUND: The investigation of relationship of tumour biological activity and the degree of tissue infiltrating lymphocytes (T4, T8, T6) and macrophages in bladder cancer was the purpose of this study. MATERIALS AND METHODS: Tumour specimens and near and distant biopsies from 26 patients suffering from superficial bladder cancer and bladder biopsies from 6 controls were studied. Monoclonal antibodies against T helper/inducer, (CD4), T suppressor/cytotoxic (CD8), Langerhans cells (CD1a) and Monocytes/Histiocytes (LeuM5) were used for the detection of lymphocyte subpopulations. Ki67 growth fractions and recurrence rate per 100 patients-months were used for the definition of the biological activity of the tumours. RESULTS: The degree of tissue infiltrating lymphocytes differed significantly between controls and both groups. Larger (but not significantly different) numbers were noticed in the non recurrence compared to the recurrence group of patients. CONCLUSIONS: We conclude that the host's immune defence mechanism against malignant cells does not seem to produce significantly different numbers of tissue infiltrating lymphocytes in tumours of low and high aggressiveness. On the other hand the degree of lymphocyte infiltration in bladder cancer is not marked compared to controls of controls of matching age.

Antiproliferative activity of interferon gamma in superficial bladder cancer.

BACKGROUND: Although the antiproliferative activity of interferon gamma has been reported in various tumours, this has not been studied in bladder cancer. Proliferative cell nuclear antigen and Ki67 growth fractions were estimated in this study in superficial bladder cancer, as a measure of the antiproliferative effect of interferon gamma. MATERIALS AND METHODS: Superficial bladder cancer samples before and after four weekly intravesical instillations of 0.7 mg IFN gamma were studied immunohistochemically for proliferative cell nuclear (PCNA) and Ki67 antigens in 25 evaluable patients. RESULTS: Ki67 growth fraction decreased from median 5% preoperatively to 1% postoperatively (p = 0.0015) and proliferating cell nuclear antigen from 20% to 5% respectively (p = 0.0001). Net reductions of both indices after the interferon instillations were significantly higher in T1 than in Ta tumours (p = 0.0431 for Ki67, and p = 0.0350 for PCNA). CONCLUSIONS: The intravesical instillations of the present dose of interferon gamma have a significant cytostatic effect on superficial bladder cancer cells as this is evidenced by the significant decrease of the growth fractions measured by means of the proliferating cell nuclear and the Ki67 antigens.

Localization of metallothionein in urothelial carcinoma of the human urinary bladder: an immunohistochemical study including correlation with HLA-DR antigen, p53, and proliferation indices.

Metallothionein (MT) is a low-molecular-weight cysteine-rich protein, which has the ability to bind and sequestrate heavy metal ions. Synthesis of MT is induced in a variety of tissues by these metal ions, as well as by endogenous factors such as glucocorticoids, interferon, interleukin-1 and vitamin D. Several lines of evidence show that MT may play a role in carcinogenesis. In this study MT expression was detected immunohistochemically, using a monoclonal antibody (E9) against a conserved epitope of I and II isoforms, in a series of 63 cases of urothelial carcinomas of the urinary bladder. Correlation between MT expression and HLA-DR antigen expression, p53, proliferation indices (PCNA and MIBI) as well as the various clinicopathological parameters, such as age, sex, squamous metaplasia, tumor grade, stage and recurrence were studied. In a semiquantitative analysis MT expression (> 10% of neoplastic cells) was observed in 12.7%, focal MT positivity in 11.1% and almost completely lack of MT expression in 76.2% of tumors. The incidence of MT expression was significantly higher (p=0.0002) in cases with high pathological tumor grades. MT values were significantly correlated with tumor stage (p=0.0009). A statistically significant positive correlation between MT expression and the HLA-DR antigen expression (p=0.001) was also detected. The data suggested that MT expression was correlated with a more aggressive behavior in urothelial bladder cancer.

Tumor markers in stage P1 bladder cancer.

BACKGROUND: The infiltration of muscularis mucosa in superficial bladder cancer has been reported to be predictive of an unfavourable course of the disease. MATERIALS AND METHODS: We studied immunohistochemically Ki-67, PCNA and p53 tumour markers in 68 P1a and Pib bladder tumours. RESULTS: A statistically significant difference (p = 0.01) was found in the distribution of grades between stages P1a and P1b, with more grade 3 and less grade 2 tumours in the latter category. Univariate analysis revealed a strong association of Ki-67 (p = 0.001) and PCNA (p = 0.032) only with stage. P53 protein expression did not have any significant association with either stage or grade. In 60 patients entered into the multivariate analysis a clearly predominant, significant effect of stage on Ki-67 (p = 0.000) was shown. CONCLUSION: Increased proliferative activity when compared to P1a is present in P1b bladder tumours, as detected by the increased expression of Ki-67 proliferating antigen. The immunohistochemical study of Ki-67 antigen may help in predicting stage P1 tumours' behaviour, even in cases where pathological distinction of P1a and P1b substages is difficult.

Lipid peroxidation and the use of emulsified propofol in laparoscopic surgery.

BACKGROUND: Free radical-induced lipid peroxidation associated with a decrease of antioxidant capacity in plasma is observed after the deflation of the pneumoperitoneum in laparoscopic surgery. In this study, we evaluated the effect of the continuous administration of lipid peroxidation derivatives on emulsified propofol. METHODS: Two groups of 20 patients each who underwent laparoscopic surgery were studied prospectively. Maintenance of anesthesia was achieved with 66% nitrous oxide and either isoflurane or continuous propofol administration. The level of thiobarbituric acid-reactive substances (TBARS) in the plasma was determined as a measure of free radicals before and after surgery. RESULTS: Ten patients in the propofol group had reduced TBARS, as compared to only one in the isoflurane group (p = 0.003). There was a statistically significant difference in age between the patients with reduced TBARS and those without reduced TBARS (p = 0.009) in the propofol group. CONCLUSIONS: Anesthesia with continuous propofol infusion in laparoscopic surgery has a significant scavenging action on the formation of free radicals and exerts its greatest antioxidant effect in patients >/=48 years of age.

CD44 standard form expression as a predictor of progression in high risk superficial bladder tumors.

OBJECTIVE: The purpose of this study was to assess the significance of the standard CD44 adhesion molecule expression in predicting progression of high risk superficial bladder carcinoma in the short term. METHODS: Sixty-six patients (51 males and 15 females, aged 27 to 89 years (mean 64.75 years) with primary superficial transitional cell bladder cancer initially treated with transurethral resection (TURBT) were enrolled in the study. Only pTa/pT1 grade 2 multiple tumors as well as all grade 3 tumors were included in this study. All tumor samples obtained after the resection were immunohistochemically evaluated for the expression of the CD44 standard molecule. Fifty eight patients remained during the follow up period which ranged from 3 to 36 months (mean 11.8 months). Tumor progression in the short term was considered as the critical end point of interest in this study. The prognostic significance of tumor stage, grade, presence of carcinoma-in-situ (CIS) and expression of CD44 in determining the risk for progression, was studied with both univariate (log rank test) and multivariate (Cox proportional hazards) methods of analysis. RESULTS: Kaplan-Meier survival curves indicated that a shorter median progression-free survival is expected for those patients with G3 bladder tumors (p = 0.0055), concomitant CIS (p = 0.0051), and loss of expression of CD44 (p = 0.0015), whereas a similar association with stage was not detected (p = 0.5793). The cox regression multivariate analysis did not yield a significant result for any of the studied parameters therefore no one of the factors taken into account can serve as an independent predictor of progression in superficial bladder cancer in the short term. CONCLUSION: The immunohistochemically detectable loss of the expression of CD44 standard form from superficial bladder tumor samples may be, complementary to the established prognostic factors, a useful predictor of tumor progression in the short term.

Simultaneous adenomectomy and preperitoneal repair of inguinal hernias by a single incision with the application of polypropylene mesh.

Preperitoneal inguinal herniorraphy in conjuction with other pelvic procedures has been described in the literature, but it has not gained wide popularity mainly due to the high recurrence rate. Recently, there has been a resurgence of interest in the preperitoneal repair of inguinal hernias with the application of mesh on the deficiency of the inguinal wall using the method commonly known as the Stoppa procedure. We evaluated the results and complications of 22 patients who underwent open surgical prostatectomy (adenomectomy) and simultaneous preperitoneal application of polypropylene mesh. Nineteen (86.4%) patients suffered from unilateral inguinal hernia whereas the remaining 3 (13.6%) had bilateral protrusions. Primary hernias only and not recurrences were included in our series. The median clinical follow-up was 20.4 months (range 9-50 months). The hernioplasty itself prolonged the whole procedure for only a few minutes and it did not affect the patients' hospitalization time (mean 6.7 days). Wound infection with subsequent development of cutaneous fistula occurred in one patient (4.5%) and treated conservatively. During follow-up one recurrence (4.5%) at the side of the previous repair of the left inguinal hernia was recorded; the protrusion was insignificant and left untreated. In all but one patient (21/22, 95.5%), the surgical results were excellent. In our experience, simultaneous transvesical adenomectomy and mesh preperitoneal hernioplasty is a convenient and safe procedure which can easily be performed by urologists in just a few minutes. The procedure which is both cost and time effective for the surgeon, achieves long-lasting beneficial results for the vast majority of patients.

Prognostic significance of angiogenesis in superficial bladder cancer.

OBJECTIVE: To assess the prognostic significance of angiogenesis parameters such as microvessel density (MVD) and vascular endothelial growth factor (VEGF) in superficial bladder cancer. PATIENTS AND METHODS: We studied 127 superficial bladder cancer samples immunohistochemically for the above factors. We compared them with standard clinicopathological features (grade, stage, concurrent in situ, multifocality, primary or recurrent status) as well as with p53 expression, recurrence and progression to muscle infiltrating disease. RESULTS: During a 36 months median follow up of 109 patients with superficial primary tumors (min. 3, max. 69 months), 80 of them recurred (73.4%), while 8 patients (7.3%) progressed to muscle invading disease. A significant correlation was noted between MVD and VEGF in all 127 samples (p = 0.019). No association was noted between MVD or VEGF with the other clinicopathological features, recurrence or progression. Although progression free survival rates of categorized microvessel density (up to and higher than median value) differed significantly only in grade 3 patients, no independent prognostic significance could be attributed to MVD. No correlation was observed between MVD or VEGF with p53 protein. CONCLUSIONS: Based on our data we suggest that VEGF is not useful for predicting recurrence or progression in superficial bladder cancer. Microvessel density determination may help to predict progression of grade 3 patients to muscle invasive disease but not as an independent prognostic factor.

Immunohistochemical prognostic markers in bladder cancer.

The management of superficial bladder cancer is characterized by early recognition of recurrence and the prevention of progression. Biological markers must provide additional information to that provided by multiplicity, size and grade. So, the identification of new prognostic biomarkers for bladder cancer could be used to divide patients into risk groups determining treatment and follow-up schemes. The transformation of a normal cell into a malignant cell is a multistep mechanism, which involves various alterations on the molecular and genetic level. Transitional-cell carcinoma (TCC) is believed to arise through a series of genetic changes. One mechanism of these changes is the mutation of normal genes to oncogenes, which allows cells to escape the regulation of cellular growth control. In addition, tumour growth is regulated by a balance between proliferation, growth arrest and programmed cell death. The control of growth arrest and apoptosis plays key roles in the development of human cancer and in cancer treatment. Tumours present a complex ecosystem in which interactions between tumour cells, extracellular matrix and host cells may lead to reciprocal influences resulting in tumour promotion, invasion and metastasis. Tumour invasion is considered to be a dynamic complex process, which involves a number of steps. During these steps, a lot of critical molecules are involved, the expression of which may offer useful information about the biological behavior of bladder cancer. This review article summarizes the most promising immunohistochemical prognostic factors which have been considered to be involved in the complex and multistep process of bladder carcinogenesis, and in the process of invasion and metastasis.

Follicular thyroid cancer metastasis to the urinary bladder: report of a case and review of the literature.

Thyroid cancer metastasis to the urinary bladder is a very rear condition. To the authors' knowledge there have been only 2 cases reported in the literature. Herein a case is reported of a metastatic bladder tumor in a 73-year-old woman with history of thyroid and breast cancer. Gross hematuria was the initial symptom of her metastatic disease. Pathology of the resected mass revealed a follicular thyroid cancer metastasis. This case illustrates that follicular carcinoma of the thyroid may have a variable presentation, including hematuria.

Prostate cancer epidemiology in a rural area of North Western Greece.

Epirus is a rural area of North-Western Greece. We reviewed data from 4 hospitals for 4.975 patients who underwent prostate biopsy in Epirus in the twelve year period from 1999 to 2010. Two six-year periods were compared (1999-2004 and 2004-2010). All cases of prostate cancer confirmed by biopsy were recorded and age-standardized incidence rates per 100,000 males were calculated. We also recorded the clinical stage for patients diagnosed in our hospital and correlated this with PSA and Gleason scores. Percentage of positive prostate biopsies was also calculated. There were a total of 1714 new cases during 1999-2010 and the mean annual age-adjusted incidence was 34/100,000. The mean incidences during 1999-2004 and 2005-2010 were 26/100,000 and 42/100,000, respectively. The mean age at diagnosis was 74. The most common Gleason score was 6 and the prevalent clinical stage was T2. Median PSA at diagnosis was 10.8 ng/ml. There was a significant difference between stage cT4 and all other stages regarding PSA value (p=0.000). A positive correlation was found between Gleason score and PSA (p=0.013). These results are in accordance with the incidence rise recorded in neighboring countries of South-East Europe. However we should keep in mind the risk of overdiagnosis and the detection of low-risk cancers that would not have caused morbidity or death during a man's lifetime anyway.

Hypoxia-inducible factors HIF-1alpha and HIF-2alpha expression in bladder cancer and their associations with other angiogenesis-related proteins.

Hypoxia-inducible factors (HIF-1alpha and HIF-2alpha) are closely related protein complexes that activate transcription of target genes in response to hypoxia. The immunohistochemical expression of these two proteins was investigated in 144 bladder cancer tissue samples and correlated with standard clinicopathological features, in order to elucidate their prognostic significance. We also evaluated their possible associations with other angiogenesis related markers such as microvessel density (MVD), vascular endothelial growth factor, thymidine phosphorylase, tenascin, fibronectin, p53 and bcl-2 to further clarify their implication in tumor stroma vascularization. Nuclear HIF-1alpha expression in tumor cells was detected in 57.1% of the cases. A trend of correlation of this expression with poorly differentiated tumors was observed. In addition, HIF-1alpha expression was positively correlated with stromal cells thymidine phosphorylase expression. Tumors that were progressed in muscle-infiltrating disease showed a higher HIF-1alpha expression. A higher HIF-1alpha expression was also observed in tumors with an in situ component. In tumor cells, low HIF-2alpha expression was observed in 6.3%, moderate in 31.9% and high in 61.8% of the cases. A trend of correlation of this expression with MVD was observed. In addition, HIF-2alpha expression was positively correlated with thymidine phosphorylase and fibronectin expression. A lower HIF-2alpha expression was detected in tumors that recurred earlier in univariate methods of analysis. HIF-2alpha was expressed in tumor stroma associated cells in 53.5% of specimens and was correlated with advance tumor stage, thymidine phosphorylase and tenascin expression. There was no statistically significant difference in the expression of both HIF-1alpha and HIF-2alpha between primary and recurrent tumors. In multivariate analysis including T stage, T grade, multifocality and T size, both HIF-1alpha and HIF-2alpha expression were not considered dependent in the prediction of recurrence or progression. In conclusion, the results of the present study indicate that HIF-1alpha and HIF-2alpha expression may help to predict recurrence or progression to muscle invasive disease but not as independent prognostic factors. In addition, the expression of HIF-1alpha and HIF-2alpha, appear to play a role in bladder cancer, vascularization possibly and in cooperation with other angiogenic factors.

Distribution of CD1a-positive Langerhans cells and lymphocyte subsets in transitional cell carcinoma of the urinary bladder. An immunohistological study on frozen sections.

The distribution of CD1a-positive Langerhans cells, CD4-positive T-helper cells, and CD8-positive T-suppressor cells in 36 patients with transitional cell carcinoma of the urinary bladder was studied immunohistochemically on frozen sections. Multiple tissue specimens from the tumour, the adjacent mucosa, and random bladder wall biopsies were examined. Langerhans cells were mainly interspersed among the tumour cells, whereas T-helper cells were present in aggregates in the stroma. T-suppressor cells were present both in aggregates in the stroma and among the tumour cells. There was a marginal relationship between the density of Langerhans cells and the density of T-helper/inducer cells and a good relationship with CD8-positive cells. There was no statistically significant difference in the population density of Langerhans cells associated with the various clinicopathological variables, including growth pattern, histological grade and stage, or patient's age and sex. On the contrary, a statistically significant difference was found in the CD1a/CD4 ratio among specimens of different grades. These results show that CD1a cell populations correlate with T-cell populations in bladder cancer, suggesting that Langerhans cells take part in the immune response carried out by T lymphocytes, their task being apparently antigen presentation.

Bilateral papillary renal cell carcinoma.

Papillary renal cell carcinoma is a subgroup of malignant renal epithelial neoplasms. We report the clinical and imaging findings of a case with multifocal and bilateral renal cell carcinoma which are nonspecific.

HLA-DR antigen expression and lymphocyte subsets in transitional cell carcinoma of the urinary bladder. An immunohistological study on frozen sections.

Lymphocyte subpopulations (B cells, CD4, CD8), interleukin-20 receptors (IL-2), monocytes/macrophages (Leu M5), and HLA-DR antigen expression were studied immunohistochemically on frozen sections from 38 bladder cancer specimens. T cells predominated over B cells in all tumours. CD4-positive lymphocytes predominated over CD8 in the stroma (CD4/CD8: 1.35/l), while in epithelial tumour cells CD8 was the prominent subpopulation (CD8/CD4: 1.75/l). Aberrant HLA-DR expression was found in 21.05 per cent of bladder tumours. A strong correlation between CD4 and CD8 population densities and macrophages with the other subpopulations was noticed. In HLA-DR-positive tumours, there was no correlation of the percentage of positive cells with CD4- and CD8-positive lymphocyte populations. Various parameters including IL-2 receptors, B cells, CD8- and CD4-positive cells, and macrophages did not differ significantly between the groups of tumours expressing and not expressing HLA-DR antigen. There were no statistically significant differences in the population densities of B cells, CD8- or CD4-positive cells, IL-2 receptor, monocytes/macrophages, and HLA-DR antigen expression among various clinicopathological parameters, including growth pattern, histological grade and clinical stage or patient's age and sex. These findings suggest that in transitional cell carcinoma of the urinary bladder, HLA-DR antigen expression is independent of lymphocyte subpopulations. It is therefore possible that HLA-DR expression by tumour cells reflect the existence of separate HLA-DR-positive or HLA-DR-negative tumour clones.