Faculty Bibliography

The present study was conducted to analyze the alterations affecting cyclins D1, E, and A in bilharzial bladder cancer and to assess their potential clinical significance. A total of 125 cases were examined. Histopathological subtypes included 68 squamous cell carcinomas, 55 transitional cell carcinomas, and 2 adenocarcinomas. Immunohistochemical analyses were performed using a panel of well-characterized antibodies. The results were correlated with proliferative index, as assessed by Ki67 antigen expression. The cyclin D1-positive phenotype, defined as the identification of positive immunoreactivity in the nuclei of >/=20% of tumor cells, was found in 33 of 107 (31%) evaluable cases. A significant association was observed between the cyclin D1-positive phenotype and deep muscle invasion (P = 0.02), high tumor grade (P = 0.02), and Ki67 high proliferative index (P = 0.03). The cyclin E-positive phenotype, defined as per cyclin D1, was found in 79 of 106 (75%) evaluable cases. The cyclin A-positive phenotype, defined using the above criteria, was identified in 60 of 108 (56%) evaluable cases. No statistically significant association was found between cyclins E or A and clinicopathological parameters or proliferative index. However, there was a strong association between the expression of cyclin D1 and the coexpression of cyclins A and/or E (P = 0.05). Ki67 proliferative index was considered high when >/=20% of tumor cells displayed positive nuclear staining, a phenotype that was observed in 99 of 115 (86%) cases. These data support the hypothesis that cyclin D1 activation determines the evolution of a particular subset of aggressive bladder tumors. In addition, cyclins E and A seem to follow an unscheduled pattern of expression, based on the high frequency of identifying a positive phenotype for these cyclins and the lack of correlation between their expression and Ki67 high proliferative index. It may be postulated that the expression of G1 cyclin genes is deregulated in bilharzial bladder cancer, and that cyclin D1 acts as an oncogenic event in these neoplasms. Moreover, the moderate number of tumors displaying the cyclin D1-positive phenotype (31%) versus the high frequency observed for both cyclins E (75%) and A (56%), suggests a short G1 disbalanced by a long S phase and a rapid transversal of the cell cycle, as evidenced by a high Ki67 index observed in 86% of these cases. This imbalance in the cell cycle, together with alterations reported on the p53 pathway, might underline the accumulation of DNA damage and the aggressive clinical course of bilharzial bladder cancer

Cytogenetic and molecular genetic analyses of prostate cancer specimens have revealed nonrandom chromosomal deletions, affecting chromosomes 7q, 8p, 10q and 16q. Based on these data, we designed this study to further characterize the altered region(s) on chromosome 16 by evaluating 16 microsatellite markers on a population composed of 32 paired normal and primary prostatic tumor samples. The 16 microsatellites selected mapped to 11 distinct loci on 16q and 5 loci on 16p. No alterations were identified affecting 16p. However, 16 of 31 (51%) informative cases showed molecular alterations in at least one of the loci analyzed on 16q, consisting of 18 deletions and 11 bandshifts. Moreover, most of the deletions clustered at 6 microsatellite loci, mapping to the 16q22.1-23.1 region. Our results suggest that microsatellite alterations on the long arm of chromosome 16 are frequent events in prostate cancer, and that the 16q22.1-23.1 region might harbor a tumor suppressor gene involved in prostate cancer

Bilharzial-related bladder carcinoma (BBC) is the most common malignant neoplasm in Egypt, also occurring with a high incidence in other regions of the Middle East and East Africa. The clinical and pathological features of BBC are different than those described for the conventional transitional cell carcinoma of the bladder, including the high incidence of squamous cell carcinoma reported in BBC and the fact that over 90% of BBC cases at presentation are advanced-stage tumors (P3 and P4). This study was conducted to better define the phenotypic alterations associated with BBC affecting the p53 cell cycle control pathway, including altered patterns of expression of downstream effector proteins such as mdm2 and p21/WAF1. A well-characterized cohort of 125 patients affected with bilharzial-related bladder tumors was studied. Tumors were classified as squamous carcinomas (n = 68), transitional cell carcinomas (n = 55), or adenocarcinomas (n = 2). The products encoded by TP53, mdm2, and p21/WAF1 genes were analyzed by immunohistochemistry. Furthermore, the patterns of expression of these molecules were correlated with the Ki67 proliferative index. In addition, the microanatomical distribution of programmed cell death was assessed in a subset of tumors, using the so-called terminal deoxynucleotidyl transferase-mediated nick end labeling method. p53 nuclear overexpression was identified in 25 (20%) of 125 cases. Nuclear overexpression of mdm2 was detected in 74 (59.2%) of 125 cases. There was a statistically significant association between coexpression of both p53 and mdm2 and detection of lymph node metastases (P = 0.04). p21/WAF1 expression was detected in 87 (72%) of 121 evaluable cases. A high Ki67 proliferative index was observed in 99 (86%) of 115 evaluable cases. There was a statistically significant association between high Ki67 proliferative index and mdm2-positive phenotype (P = 0.005) and deep muscle invasion (P3b; P = 0.026) as well as lymph node metastases (P = 0.039). Apoptosis was observed in terminally differentiated tumor cells identified in the superficial layers of well-differentiated squamous carcinoma or exfoliating cells in transitional lesions. However, only rare apoptotic tumor cells were found in basal or suprabasal layers as well as in the invasive elements of the neoplasms studied. These results suggest that the frequency of p53 nuclear overexpression in BBC is lower than that reported for conventional transitional cell carcinoma. Nevertheless, tumors with p53 alterations have a greater propensity to progress. The prominent number of cases displaying an mdm2-positive phenotype suggests that this may be an early incident in BBC and should be regarded as a potential oncogenic phenomenon. This is supported by the significant correlation between high Ki67 proliferative index and mdm2 overexpression. The association of an aggressive clinical course with the coexpression of both p53 and mdm2 products might be viewed as a cooperative effect that develops in tumor progression