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Cervical cancer is the second most common cancer in women worldwide. Human papillomavirus (HPV) infection appears to be a necessary factor in the development of almost all cases (>95%) of cervical cancer. HPV E6 induces a change of control of p53 stabilization from Hdm2 to E6/E6AP in HPV‑infected cells. It is well known that the LxxLL motif of cellular ubiquitin ligase E6AP binds to the pocket of E6 and causes a conformational change to enable E6 to bind p53 competently. In the ternary complex E6/E6AP/p53, p53 is polyubiquitinated by E6AP and subsequently degraded by a proteasome. Therefore, these cells are deficient in the processes regulated by p53, including apoptosis, damaged DNA repair, and the cell cycle. In the present study, it was demonstrated that quercetin induced G2 phase cell cycle arrest and apoptosis in both HeLa and SiHa cells, accompanied by an increase of p53 and its nuclear signal. It was also observed that quercetin increased the level of the p21 transcript and the pro‑apoptotic Bax protein, which are two p53‑downstream effectors. However, quercetin did not alter the expression of the HPV E6 protein in cervical cancer cells; therefore, the increase in p53 occurred in an E6 expression‑independent manner. Furthermore, molecular docking demonstrated that quercetin binds stably in the central pocket of E6, the binding site of E6AP. These data suggest that quercetin increases the nuclear localization of p53 by interrupting E6/E6AP complex formation in cervical cancer cells.

At present, prostate-specific antigen (PSA) is used as a clinical biomarker for prostate cancer (PCa) diagnosis; however, a large number of patients with benign prostate hyperplasia (BPH) with PSA levels in the 'gray area' (4-10 ng/ml) are currently subjected to unnecessary biopsy due to overdiagnosis. Certain microRNAs (miRs) have been proven to be useful biomarkers, several of which are detectable in bodily fluids. The present study identified and validated a urinary miR‑based signature to enhance the specificity of PCa diagnosis and to reduce the number of patients with benign conditions undergoing biopsy. Seventy‑three urine samples from Mexican patients with diagnosis of PCa with a Gleason score ≥7 and 70 patients diagnosed with BPH were collected after digital rectal examination (DRE) of the prostate. miR expression profiles were determined using TaqMan Low Density Array experiments, and normalized Ct values for the miRs were compared between PCa and BPH groups. Receiver operating characteristic (ROC) curve analysis was performed to evaluate whether miR detection in urine is suitable for distinguishing patients with PCa from those with BPH. The identified miR‑100/200b signature was significantly correlated with PCa. Using a multivariable logistic regression approach, a base model including the clinical variables age, prostate‑specific antigen (PSA), the percentage of free PSA and DRE was generated, and a second base model additionally contained the miR‑100/200b signature. ROC analysis demonstrated that the combined model significantly outperformed the capacity of PSA (P<0.001) and the base model (P=0.01) to discriminate between PCa and BPH patients. In terms of evaluation of the sub‑group of patients in the gray zone of PSA levels, the performance of the combined model for predicting PCa cases was significantly superior to PSA level determination (P<0.001) and the base model (P=0.009). In addition, decision curve analysis demonstrated that the use of the combined model increased the clinical benefit for patients and produced a substantial reduction in unnecessary biopsies across a range of reasonable threshold probabilities (10‑50%). Detection of the urinary miR signature identified in the present study as part of clinical diagnostic procedures will enhance the accuracy of PCa diagnosis and provide a clinical benefit for patients with BPH by sparing them from undergoing invasive biopsy. To the best of our knowledge, the present study was the first to describe the profiling of urinary miR100 and miR-200b levels for the clinical diagnosis of PCa.

It has been found that certain cytokines (IL-4, IL-10 and TGF-β1) are highly expressed locally in biopsies from patients with premalignant lesions and cervical cancer, and may induce a local immune-suppression state. In particular, IL-10 is highly expressed in tumor cells and its expression is directly proportional to the development of HPV-positive cervical cancer, suggesting an important role of HPV proteins in the expression of IL-10. In fact, we demonstrated that E6 and E7 HPV proteins regulate TGF-β1 gene expression in cervical cancer cells. Here, we found by band shifting analysis that the HPV E2 protein binds to the regulatory region of the human IL-10 gene (-2054 nt) and induces high promoter activity in epithelial cells. Additionally, cervical cancer cells transfected to express the HPV E2 protein induce elevated levels of IL-10 mRNA in human papillomavirus-infected cells. The elevated expression of IL-10 may allow for virus persistency, the transformation of cervical epithelial cells, and consequently cancer development.