The retinoblastoma protein/p16 INK4A pathway but not p53 is disrupted by human papillomavirus in penile squamous cell carcinoma.

AIMS: The pathogenesis of penile squamous cell carcinoma (PSCC) is not well understood. Human papillomavirus (HPV) may be involved in carcinogenesis, but few studies have compared cell-cycle protein expression in HPV positive and negative cancers. The aim was to determine the extent of HPV infection in different histological subtypes of PSCC and its impact on the expression of key cell-cycle proteins: p53, p21, p16(INK4A) and retinoblastoma (RB) protein. METHODS AND RESULTS: One hundred and forty-eight PSCC samples were examined immunohistochemically for RB, p16(INK4A) , p53 and p21 protein expression. One hundred and two cases were typed for HPV by PCR. HPV DNA was detected in 56% of tumours, with HPV16 present in 81%. Basaloid tumours were related strongly to HPV infection (10 of 13), while verrucous were not (three of 13). Fifty-nine per cent (38 of 64) of usual type SCCs had HPV infection. RB protein correlated negatively (P<0.0001) and p16(INK4A) (P<0.0001) and p21 (P=0.0002) correlated positively with HPV infection. p53 did not correlate with HPV infection. CONCLUSIONS: HPV infection is present in more than half of penile cancers and it is responsible for RB pathway disruption. However, no link between HPV and p53 immunodetection was found. Only basaloid and half of usual-type PSSCs correlate with HPV infection, confirming possible separate aetiologies for those tumours.

HPV infection and immunochemical detection of cell-cycle markers in verrucous carcinoma of the penis.

Penile verrucous carcinoma is a rare disease and little is known of its aetiology or pathogenesis. In this study we examined cell-cycle proteins expression and correlation with human papillomavirus infection in a series of 15 pure penile verrucous carcinomas from a single centre. Of 148 penile tumours, 15 (10%) were diagnosed as pure verrucous carcinomas. The expression of the cell-cycle-associated proteins p53, p21, RB, p16(INK4A) and Ki67 were examined by immunohistochemistry. Human papillomavirus infection was determined by polymerase chain reaction to identify a wide range of virus types. The expression of p16(INK4A) and Ki67 was significantly lower in verrucous carcinoma than in usual type squamous cell carcinoma, whereas the expression of p53, p21 and RB was not significantly different. p53 showed basal expression in contrast to usual type squamous cell carcinoma. Human papillomavirus infection was present in only 3 out of 13 verrucous carcinomas. Unique low-risk, high-risk and mixed viral infections were observed in each of the three cases. In conclusion, lower levels of p16(INK4A) and Ki67 expressions differentiate penile verrucous carcinoma from usual type squamous cell carcinoma. The low Ki67 index reflects the slow-growing nature of verrucous tumours. The low level of p16(INK4A) expression and human papillomavirus detection suggests that penile verrucous carcinoma pathogenesis is unrelated to human papillomavirus infection and the oncogenes and tumour suppressor genes classically altered by virus infection.

Human papillomavirus is detected in transitional cell carcinoma arising in renal transplant recipients.

AIMS: We investigated the role of human papillomavirus (HPV) in the development of transitional cell carcinoma (TCC) arising in renal transplant recipients. METHODS: Genomic DNA was extracted from 10 microm paraffin embedded sections of five TCCs arising in five renal transplant recipients using the QIAamp DNA mini kit according to the manufacturer's instructions. beta-globin PCR was performed to test DNA adequacy. Samples were tested for the presence of HPV DNA by broad spectrum HPV PCR method using non-biotinylated SPF10 primers (SPF1A, SPF1B, SPF1C, SPF1D, SPF2B, SPF2D) which amplify a short 65 bp fragment. Positive bands were identified on a 3% gel. Positive samples underwent a second HPV PCR and were amplified using biotinylated SPF10 primer set, which amplifies the same 65 bp region of the L1 open reading frame. INNO-LiPA line probe assay was then performed to genotype the samples which uses a reverse hybridisation principle. RESULTS: Four of five TCCs examined were positive for HPV. The high risk HPV16 was detected in three cases whereas in the fourth case an unclassifiable HPV genotype was present. In all DNA samples, beta-globin amplification was successful. CONCLUSIONS: Our results indicate that HPV and in particular HPV16 may play an aetiological role in the development of TCC in renal transplant patients.

Hedgehog signalling in androgen independent prostate cancer.

OBJECTIVES: Androgen-deprivation therapy effectively shrinks hormone-naïve prostate cancer, both in the prostate and at sites of distant metastasis. However prolonged androgen deprivation generally results in relapse and androgen-independent tumour growth, which is inevitably fatal. The molecular events that enable prostate cancer cells to proliferate in reduced androgen conditions are poorly understood. Here we investigate the role of Hedgehog signalling in androgen-independent prostate cancer (AIPC). METHODS: Activity of the Hedgehog signalling pathway was analysed in cultured prostate cancer cells, and circulating prostate tumour cells were isolated from blood samples of patients with AIPC. RESULTS: AIPC cells were derived through prolonged culture in reduced androgen conditions, modelling hormone therapy in patients, and expressed increased levels of Hedgehog signalling proteins. Exposure of cultured AIPC cells to cyclopamine, which inhibits Hedgehog signalling, resulted in inhibition of cancer cell growth. The expression of the Hedgehog receptor PTCH and the highly prostate cancer-specific gene DD3(PCA3) was significantly higher in circulating prostate cancer cells isolated from patients with AIPC compared with samples prepared from normal individuals. There was an association between PTCH and DD3(PCA3) expression and the length of androgen-ablation therapy. CONCLUSIONS: Our data are consistent with reports implicating overactivity of Hedgehog signalling in prostate cancer and suggest that Hedgehog signalling contributes to the androgen-independent growth of prostate cancer cells. As systemic anti-Hedgehog medicines are developed, the Hedgehog pathway will become a potential new therapeutic target in advanced prostate cancer.

Human papillomavirus testing with conventional Pap smear screening in three inner London community clinics.

BACKGROUND AND METHODOLOGY: This observational study aimed to establish prevalence of high-risk human papillomaviruses (hrHPV) in women attending three inner London community clinics for routine screening and to pilot hrHPV testing in the triage of either borderline or negative cytology after previous abnormalities. Hybrid Capture 2 was carried out on brush samples taken alongside conventional smears from 1434 women aged 20-49 years. hrHPV positivity prompted earlier referral of women with previous abnormalities and either low-grade or negative cytology. Outcome at colposcopy was compared with the records of 1871 women aged 20-49 years attending colposcopy during the same period of time (routine colposcopies). RESULTS: hrHPV was detected in 111/161 (68.9%) women with abnormal cytology, 76/460 (16.5%) with negative cytology after previous abnormalities and 105/813 (12.9%) with negative cytology and no previous abnormalities. Overall, hrHPV was detected in 292/1434 (20.4%) women in the study (95% CI 18.3-22.5). hrHPV prevalence increased with severity of cytological abnormality (p<0.001) and decreased with age both with negative and low-grade cytology (p<0.001). High-grade cervical intraepithelial neoplasia (CIN) biopsies were found more frequently in women in the study groups with low-grade (p<0.001) or negative cytology than in routine colposcopies, but more women in the study groups attended colposcopy (8.2% compared with 4.1% routine colposcopies, p<0.001). CONCLUSIONS: hrHPV positivity increased detection of high-grade CIN in the study groups at the expense of more colposcopies. hrHPV negativity could reduce the need for investigation of low-grade cytology in women aged over 35 years and for surveillance after previous abnormalities.