myc Family DNA Amplification in 107 Tumors and Tumor Cell Lines from Patients with Small Cell Lung Cancer Treated with Different Combination Chemotherapy Regimens

We studied 107 specimens (38 tumors and 69 tumor cell lines) from 90 patients with small cell lung cancer to determine the characteristics and clinical situations of patients from whom tumor cell lines could be established and the myc family DNA copy number. The proportion of extensive stage small cell lung cancer patients from whom a tumor cell line could be established prior to the initiation of therapy increased during the 10 years of the study (P < 0.001). Amplification of one of the myc family genes occurred in 3 of 40 (8%) of the untreated patient specimens compared to 19 of 67 (28%) of the treated patient specimens (P = 0.01). The myc family DNA amplification occurred in 17 of 54 (31%) of the specimens from patients treated with cyclophosphamide-based combinations and 2 of 13 (15%) of the specimens from patients treated with etoposide/cisplatin (P = 0.25). Both tumors and tumor cell lines were obtained from 17 patients with small cell lung cancer and the myc family DNA copy number was similar in 16 of the 17 patients. We conclude that: (a) myc family DNA amplification occurs more commonly in specimens from treated than untreated patients; (b) there are no prominent differences in the frequency of amplification following treatment with different chemotherapy regimens; and (c) myc family DNA amplification is similar in tumors and tumor cell lines from the same patients.