No abstract

Alterations in the p16/cyclinD1/Rb and ARF/Mdm2/p53 pathways are frequent events in the pathogenesis of squamous cell carcinomas. Different mechanisms of p16 regulation have been described for penile carcinomas so far. Therefore, expression of p16 and p53 was immunohistochemically detected with monoclonal antibodies in 52 primary invasive penile squamous cell carcinomas. The carcinomas were analyzed for allelic loss (LOH) in p16(INK4A) and p53, as well as for mutations in the p16(INK4A) and the p53 gene. In addition, we examined the promoter status of p16(INK4A) by methylation-specific PCR. The presence of human papilloma virus (HPV) 6/11, HPV 16 and HPV 18 DNA was analyzed by PCR. Data were compared to clinical data. Concerning p16, 26 (50%) tumors showed positive immunohistochemistry, 32 (62%) tumors showed allelic loss and 22 tumors (42%) showed promoter hypermethylation. All tumors with negative p16 immunohistochemistry showed LOH near the p16(INK4A) locus and/or hypermethylation of the p16(INK4A) promoter. HPV 16 DNA was detected in 17 tumors, ten of them with positive p16 immunostaining. The remaining seven tumors with negative p16 staining showed allelic loss and/or promoter hypermethylation. Evidence of lymph node metastasis was significantly associated with negative p16 immunohistochemistry as well as with combined LOH and promoter hypermethylation (p = 0.003 and p = 0.018, respectively). Allelic loss around p53 was found in 22 tumors (42%), and seven mutations of the p53 gene could be demonstrated in our tumors. No correlations could be found between any p53 alteration and clinical parameters.

In patients with PC, the expression of p53 in the primary tumour specimen can be reproducibly assessed and is negatively associated with cancer specific survival.

In penile squamous cell carcinoma (PSCC), the outcome largely depends on early detection and resection of inguinal lymph node metastases. We investigated the role of metastasis suppressor protein kang ai 1 (KAI1)/cluster of differentiation 82 (CD82), which is known to be of prognostic significance for a wide variety of cancers. Moreover, we analysed the tumours for human papillomavirus (HPV) DNA and loss of heterozygosity at the 11p11.2 locus. Tissue samples of 30 primary PSCCs were investigated immunohistochemically using an anti-KAI1/CD82 polyclonal antibody. The expression was assessed according to the degree of KAI1/CD82-positive tumour cells as positive, decreased or negative. The presence of HPV6/11, HPV16 and HPV18 DNA was analysed by polymerase chain reaction. All patients with decreased or negative expression of KAI1/CD82 in primary lesions had lymph node metastases (p = 0.0002). Patients with positive KAI1/CD82 expression showed a significant better prognosis for survival compared to the other groups (p = 0.0042). Presence of HPV DNA was associated with decreased or negative KAI1/CD82 expression. Lacking or decreased expression of metastasis suppressor gene KAI1/CD82 appears to be a prognostic parameter for the occurrence of lymph node metastases in PSCC. Our study suggests an association of decreased KAI1/CD82 expression with tumour progression, development of metastases and disease-specific death.

We evaluated HER2 expression profiles in 32 carcinoma in situ (CIS) and 31 non-CIS conditions (5 dysplasia and 26 reactive atypia) of the urinary bladder mucosa by applying breast cancer scoring rules. In situ hybridization was performed on tissue microarrays to assess HER2 gene amplification status. Our immunoprofiling data disclosed moderate to strong HER2 expression in CIS, including the basal layer of the urothelium, and absent to weak HER2 expression in non-CIS conditions. From the histologic differential diagnostic standpoint, immunostaining for HER2 protein represents a useful adjunct to aid in the delineation between CIS and non-CIS conditions of the bladder mucosa. Pathogenically, aberrant HER2 protein expression in CIS seems to be more commonly associated with polysomy than with gene amplification. From a therapeutic viewpoint, prospective clinical studies should investigate the potential benefit of HER2-targeted therapies in CIS, particularly in cases unresponsive to conventional therapeutic regimens.

Since reliable molecular prognostic parameters for inguinal lymph metastases in penile cancer are not available, tumor grading is often used as a surrogate prognostic tool for the indication of inguinal lymphadenctomy and has been integrated into the current TNM classification for penile cancer. The reliability of tumor grading is under discussion. We examined interobserver grading variability in 90 primary penile carcinomas, assessed by 12 different uropathologists from five European countries. Tumor grading, following the CAP scheme, was compared, and interobserver variability was calculated using kappa statistics. The interobserver variability was high as reflected by an overall low kappa coefficient (mean k = 0.34) and reached a moderate level only in 26.4 % of the cases (range 0.02-0.67). The percentage of G1 tumors assigned ranged from 8.6 to 52.5 %, G2 tumors from 27.1 to 72.6 % and G3 tumors from 11.7 to 48.7 %. Only some observers assigned G4 with a range of 0.6-21.9 %. Subdivision into low and high grade according to UICC and EAU classifications differed significantly (P < 0.001). Low reproducibility of grading in penile carcinomas with the favored method does not allow a reliable prognostication of tumor aggressiveness. Inclusion of histological grading into the TNM classification currently seems not to be a benefit.

The MIB-1 antibody is a useful adjunct in the differential diagnosis of conventionally challenging flat lesions of the bladder mucosa. In particular, 16% or more Ki67 positive cell nuclei favours CIS over flat non-CIS conditions, whereas 15% or less Ki67 positive cell nuclei is supportive of non-CIS conditions. However, due to some important limitations of MIB-1 staining, the MIB-1 antibody should be used as a component of a panel.

Expression of ANXs was different in histologic subtypes of penile carcinomas. Strong expression of ANX AI and ANX AIV in the invasion front seems to indicate a higher risk of lymph node metastasis.