Mutational profiling of bone metastases from lung adenocarcinoma: results of a prospective study (POUMOS-TEC).

Targeted therapies have improved patient survival in metastatic lung adenocarcinoma. Molecular diagnosis is a key element to identify oncogenic drivers predicting the efficacy of these agents. In stage IV patients, histopathological diagnosis is often performed on bone metastases biopsy, but routine procedure of decalcification may alter DNA quality for subsequent molecular tests. We set up a procedure to perform molecular analyses on bone metastasis and describe the results of mutational profiling. POUMOS-TEC is a prospective study conducted in stage IV lung adenocarcinomas. Bone metastasis specimens from surgery and CT-scan guided biopsies were sent fresh for immediate formalin-fixation. Decalcification was performed, only when necessary, using EDTA. Controls were processed with acid decalcification. DNA extraction was performed after laser microdissection. Mutational profiling of oncogenic drivers was conducted as recommended by the French National Cancer Institute. Diagnosis efficiency of the computed tomography (CT)-scan guided biopsy process was assessed. Among 177 collected bone metastases specimens, 49 came from lung adenocarcinomas. Specimens processed with no decalcification or EDTA (n=45) provided high-quality DNA. Molecular profiling was performed in 44/45 (98%) of cases. The results of the whole panel of oncogenic drivers (EGFR, KRAS, BRAF, PIK3CA, HER2 and ALK) were obtained in 41/45 (91%) of cases. A mutation was observed in 50% of cases including 32% of KRAS and 14% of epidermal growth factor receptor (EGFR) mutations. CT-scan biopsy efficiency rate was 96%. We demonstrated the feasibility to routinely conduct mutational profiling on bone metastases biopsies. We observed a higher rate of EGFR mutations (+42%) in comparison with the average rate of all stage IV lung adenocarcinomas. This procedure is a new step toward the goal of personalized medicine to treat lung cancers and other osteophilic tumors.