Novel palliative strategies for patients with androgen-independent prostate cancer (AIPC) include targeting the epidermal growth factor receptor (EGFR) family. The aim of the present study was to investigate intrapatient changes of EGFRs during the development of AIPC. In total, 106 symptomatic AIPC patients were identified in whom prostatic biopsies (adenocarcinoma) were available both before the start of androgen deprivation (PRTR biopsy) and after the development of AIPC (AIPC biopsy). All four known subgroups of the EGFR family were determined by immunohistochemistry (IHC): c-erbB-1 (EGFR), c-erbB-2 (HER2/neu), c-erbB-3 (HER3) and c-erbB-4 (HER4). Moderate to strong membrane-specific staining was recorded semiquantitatively (o10% vs X10% ¼ IHC stained tumour cells: 'negative' vs 'positive' staining). The medical records were reviewed for clinical variables. During the development of AIPC, intrapatient changes occurred in two opposite directions for each of the four EGFRs: negativity changed to positivity, and vice versa, statistically significant only for the increase of c-erbB-1 expression (P ¼ 0.001). The c-erbB-2 expression in the AIPC biopsy was associated with a significantly shorter survival from the time of the AIPC biopsy (P ¼ 0.029). Our results support ongoing therapeutic attempts of EGFR inhibition in subgroups of patients with prostate cancer. Further research is needed to understand the function of EGFRs in this malignancy.

Pre- and post-treatment specimens from 47 patients with hormone resistant prostatic carcinoma were compared with each other regarding histological grade and immunoreactivity for p53 protein, neuron specific enolase and c-erbB-2 protein. Significantly more specimens expressed a high malignancy grade when the tumour had become hormone resistant than at the time of initial diagnosis (Gleason P: < 0.0001, WHO P:0.0003). p53 protein immunoreactivity increased significantly with disease progression (P:0.006), while tissue PSA immunoreactivity was reduced in post-treatment specimens (P:0.011). p53 protein expression did not correlate with histological grade or PSA expression and seems to be an independent parameter which participates late in the neoplastic transformation. Thirty-two percent of the tumours were neuron specific enolase positive, but this parameter did not correlate with development of hormone resistance. c-erbB-2 protein reactivity was not recognised. Images Figure 1

Four different genes were identified by immunoscreening of a cDNA expression library from the human prostate cancer cell line DU145 with allogeneic sera from four prostate cancer patients. A cDNA encoding the nucleolar protein No55 was further analysed and shown to be expressed at the mRNA level in several normal tissues, including ovaries, pancreas and prostate and in human prostate cancer cell lines PC-3, PC-3m and LNCaP. By reverse transcriptase/polymerase chain reaction, expression of No55 was several-fold higher in two out of nine prostate cancer primary tumours and two out of two metastatic lesions, compared to normal prostate tissue. Antibodies to No55 were detected in sera from seven out of 47 prostate cancer patients but not in sera from 20 healthy male controls. Sequence analysis of the No55 open reading frame from normal and tumour tissues revealed no tumour-specific mutations. The No55 gene was located to chromosome 17q21, a region reported to be partially deleted in prostate cancer. Considering the immunogenicity of the No55 protein in the tumour host, the expression profile and chromosomal localization of the corresponding gene, studies evaluating No55 as a potential antigen for immunological studies in prostate cancer may be warranted. © 2000 Cancer Research Campaign

Summary Tissue specimens from 150 patients with localised prostatic carcinomas and 116 patients with prostatic carcinomas with distant metastases were analysed for histological grade (WHO and Gleason) and immunoreactivity for prostate acid phosphatase (PAP), prostate-specific antigen (PSA), neurone-specific enolase (NSE), p53 protein, c-erbB-2 protein, cytokeratins (AEI/AE3) and vimentin. After stratification for the presence or absence of distant metastases, multivariate regression analysis revealed that WHO grading was the most powerful independent prognosticator, followed by age and prostate acid phosphatase expression. There was a trend towards reduced survival with decreasing prostate-specific antigen reactivity. The Gleason system showed poor prognostic ability. The analysis predicted reduced survival in the presence of extensive neurone-specific enolase reactivity, mostly because of one case of small-cell carcinoma.

Expression of c-erbB-2 protein, neuron-specific enolase (NSE) and DNA ploidy was studied by immunohistochemistry and flow cytometry in formalin-fixed and paraffin-embedded specimens from 104 patients with locally advanced transitional cell carcinoma of the bladder. Positive membrane bound c-erbB-2 staining was found in 15% of the tumours, and 38% of the tumours were positive for NSE. Only one tumour stained positively for both NSE and c-erbB-2. Expression of c-erbB-2 protein and NSE was neither correlated to tumour stage nor to histopathological grade. The frequency of non-diploid tumours was 78% in 49 c-erbB-2/NSE negative tumours, 98% in 40 NSE positive tumours, and 100% in 16 c-erbB-2 positive tumours (P = 0.004). Whether the c-erbB-2 expression is a useful prognostic marker in addition to other conventional parameters, remains to be shown.