Penile and uterine cervical squamous cell carcinomas: A comparative genomic profiling study.

Abstract

514 Background: Metastatic penile (mPSCC) and uterine cervical squamous cell carcinoma (mCSCC) are aggressive forms of malignancy with limited treatment options. We used comprehensive genomic profiling (CGP) to compare the genomic alterations (GA) and their potential impact on targeted and immunotherapy options of mPSCC and mCSCC. Methods: 78 metastatic mPSCC and 604 mCSCC underwent CGP using a hybrid-capture-based next-generation sequencing assay with a mean coverage depth of > 500X. Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. Results: The median age of mPSCC men was higher than mCSCC women. The HPV+/CDKN2A- status was more frequent in the mCSCC than mPSCC. The GA/tumor were similar for both tumor types (table). TP53 mutations were more common in mPSCC likely linked to loss of original HPV+ status. TERT, NOTCH1 and FAT1 GA were more frequent in mPSCC whereas PIK3CA GA were more common in mCSCC. MTOR pathway targets (GA in STK11, FBXW7 and PTEN) were more common in mCSCC. MSI-High status was extremely rare in all cases, but the relatively high frequencies of TMB ≥ 10/20 mut/Mb in both mPSCC and mCSCC were noteworthy. Examples of patients with mCSCC and mPSCC responding to targeted and immunotherapies will be presented. Conclusions: Although mCSCC and mPSCC share a variety of genomic features, the 2 tumor types can nonetheless be sharply differentiated on CGP. The TP53, CDKN2A and HPV status of the tumor types differ significantly with viral identification much higher in the mCSCC group. There are opportunities for targeted therapies in both groups predominantly identified in the MTOR pathway. Numerous cases with significantly elevated TMB in both mPSCC and mCSCC suggest that immunotherapies might be of benefit in a subset of patients. [Table: see text]