Human papillomavirus infection as a prognostic factor in oropharyngeal squamous cell carcinomas treated in a prospective phase II clinical trial.

UNLABELLED: The aim of this study was to determine the presence of high-risk HPV-16 in patients with HNSCC, assess the impact of HPV status on treatment response and survival in this select cohort treated with combined modality therapy and to identify the differences in HIF-1alpha and VEGF expression in HPV-positive and -negative tumors. PATIENTS AND METHODS: Patients had resectable, untreated stage III, IV HNSCC of the oral cavity, oropharynx, hyopharynx or larynx, and stage II cancer of the base of tongue, hypopharynx and larynx. HPV status was determined by conventional PCR in fresh frozen biopsy samples and by Taqman PCR assay on formalin-fixed, paraffin-embedded specimens. HIF-1alpha and VEGF expression were assessed by quantitative real-time PCR (RT-PCR). Multivariate Cox proportional hazards regression analysis was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) based on HPV status. RESULTS: HPV-16 was detected in 14 of 24 evaluable cases. There were no significant differences in response rates after neoadjuvant chemotherapy (86% vs. 90%) in HPV-positive and HPV-negative patients, respectively. There was a trend toward better progression-free (HR=0.15, 95% CI=0.002-12.54; p=0.06) and overall survival (HR=0.14, 95% CI=0.001-14.12; p=0.10) for HPV-positive patients. In a subset of 13 fresh frozen samples, RT-PCR revealed a significant increase in VEGF mRNA levels in HPV-positive tumors (p<0.01). No difference was seen for HIF-1alpha expression. CONCLUSION: HPV presence portended a better prognosis in patients with oropharyngeal SCC treated with a multimodality treatment in a prospective clinical trial. The level of VEGF mRNA was up-regulated in HPV-16-positive tumors possibly through an HIF-1 independent manner.

Update on HER-kinase-directed therapy in prostate cancer.

The human epidermal growth factor receptor (HER) family of receptor tyrosine kinases is part of a network of pathways that are involved in the development and progression of prostate cancer. HER-kinase receptors include epidermal growth factor receptor (EGFR), HER2, HER3, and HER4, which must combine as dimers to affect signaling. Different combinations of receptors produce different qualities and levels of pathway activation. Among HER-family receptors, HER2 activation is particularly important in breast cancer, as HER2 gene amplification is associated with a distinct clinical course and response to treatment with a HER2-directed therapy (trastuzumab). Although HER2 can be over-expressed in prostate cancer, there is no clinical data to support the use of trastuzumab for prostate cancer patients. Preclinical and clinical data show that the activation of the HER-kinase axis is important for the progression of prostate cancer to androgen-independent disease. Data points towards the importance of inhibiting multiple members of the HER-kinase family to achieve more complete blockade of this axis for cancers other than HER2-overexpressing breast cancer. Multiple pharmaceutical agents that block the HER-kinase axis are currently being tested for patients with prostate cancer. These include antibodies, tyrosine kinase inhibitors, and novel strategies which seek to decrease HER2 expression.

In vitro selection of external guide sequences for directing RNase P-mediated inhibition of viral gene expression.

External guide sequences (EGSs) are small RNA molecules that bind to a target mRNA, form a complex resembling the structure of a tRNA, and render the mRNA susceptible to hydrolysis by RNase P, a tRNA processing enzyme. An in vitro selection procedure was used to select EGSs that direct human RNase P to cleave the mRNA encoding thymidine kinase (TK) of herpes simplex virus 1. One of the selected EGSs, TK17, was at least 35 times more active in directing RNase P in cleaving TK mRNA in vitro than the EGS derived from a natural tRNA sequence. TK17, when in complex with the TK mRNA sequence, resembles a portion of tRNA structure and exhibits an enhanced binding affinity to the target mRNA. Moreover, a reduction of 95 and 50% in the TK expression was found in herpes simplex virus 1-infected cells that expressed the selected EGS and the EGS derived from the natural tRNA sequence, respectively. Our study provides direct evidence that EGS molecules isolated by the selection procedure are effective in tissue culture. These results also demonstrate the potential for using the selection procedure as a general approach for the generation of highly effective EGSs for gene-targeting application.