Establishment and characterization of preclinical model of primary ovarian squamous cell carcinoma

Primary ovarian squamous cell carcinoma (POSCC) represents an exceedingly rare subtype of epithelial ovarian cancer (EOC) characterized by a cryptic etiology and insidious onset. The rarity and high mortality associated with pure primary ovarian squamous cell carcinoma (SCC) make it challenging to conduct large randomized controlled studies. Furthermore, there are currently no commercially available ovarian SCC cell lines for research purposes, necessitating the urgent establishment of novel lines. To our knowledge, this study reports the first preclinical model of primary ovarian squamous cell carcinoma (POSCC), denoted as ZOC254. We have detailed the establishment and characterization of ZOC254, derived from a 64-year-old female patient, which preserves the primary tumor's original traits across various levels during prolonged in vitro expansion. Whole-exome sequencing (WES) of both the primary tumor and derived cell line revealed homologous recombination deficiency (HRD) and high tumor mutational burden (TMB). ZOC254 also exhibited the PIK3CA: p.E542K mutation associated with targeted therapy. The effectiveness of olaparib, everolimus, and conventional chemotherapeutic agents for ovarian cancer was preliminarily assessed on the growth of patient-derived cells (PDC). The POSCC cell line and derived xenograft transplantation model reported in this study serve the purpose of broadening the resources accessible for preclinical investigations into ovarian squamous carcinoma.