The primary tumor (sample #1), pleural metastases (sample #2), and malignant cells from ascites (sample #4) were all found to carry point mutations in SCN1B, PPP1R3A, and ZYG11A. However, APBA2, ZNF142, and RBFOX1 mutations, although not present in the primary tumor, were detected in both metastatic (chemotherapy refractory) specimens. The gene discussed is SCN1B; the disease is neoplasm.