Abstract
Pleomorphic rhabdomyosarcoma (PRMS) is an extremely rare soft tissue tumor with dismal prognosis that has a higher incidence in adults compared to the other RMS subtypes. The unique PRMS cell line BH1522 was established from a pleural effusion of a lung metastasis and the characteristics of this cell line were compared to two embryonal type RMS (ERMS) cell lines. The affected patient had been treated by surgery, several cycles of chemotherapy and thoracoscopy of the lung metastases. Chemosensitivity of the PRMS cell lines was checked using cytotoxicity assays and oncogene-related and phosphoproteins by Western blot arrays. The BH1522 cell line proved to be chemosensitive to conventional chemotherapeutics and the Son of Sevenless 1 homolog (SOS1) inhibitor BAY-293 that inhibited proliferation and suppressed MYC activity. Results of the novel functional BH1522 tests corroborate published tumor sequencing data that demonstrated alterations in receptor tyrosine kinase/MAPK, PI3K/AKT and mutated p53 as suspected drivers of malignant growth.