Overexpression of ID1 promotes tumor progression in penile squamous cell carcinoma.

Penile squamous cell carcinoma (PSCC) occurs more frequently in developing countries, and is commonly diagnosed at an advanced stage with an unfavorable prognosis. At present, few biomarkers for PSCC have been identified and used in clinical practice. Aberrant expression of inhibitor of DNA binding 1 (ID1) has been suggested as a potential regulator of tumor progression in various types cancer. Herein, we evaluated ID1 expression in PSCC and analyzed its association with the clinicopathological parameters of PSCC. Our findings indicated that ID1 overexpression is associated with histological subtype and lymph node metastasis. Kaplan‑Meier survival analysis showed that the overexpression of ID1 is associated with unfavorable cancer‑specific survival. In Cox proportional hazard models, ID1 overexpression was found to be an independent predictor of cancer‑specific survival. Furthermore, we investigated the function of ID1 in PSCC using a PSCC cell line Penl1. Silencing of ID1 expression retarded cell growth, inhibited clonogenesis, and attenuated cell migration and invasion in Penl1 cells. ID1 may regulate key oncogenic and metastasis‑related molecules, as depletion of ID1 expression affected the levels of p‑AKT, p16, PTEN and cleaved caspase‑3, and reduced MMP2/9 secretion in Penl1 cells. Nevertheless, the mRNA expression of p16 and PTEN increased following ID1 knockdown, suggesting that ID1 may repress p16 and PTEN expression in Penl1 cells. Therefore, overexpression of ID1 could serve as a potential prognostic biomarker for the clinical management of PSCC. Strategies targeting ID1‑regulated signaling pathways may have therapeutic benefit in PSCC.