Differential molecular markers of primary lung tumors and metastatic sites indicate different possible treatment selections in patients with metastatic lung adenocarcinoma.

PURPOSE: Detecting different molecular markers in primary tumors and metastases may provide therapeutic information. Here we investigated differences between primary tumors and four metastatic sites of lung adenocarcinoma in the biomarkers' features and discussed potential therapeutic implications.

METHODS: A total of 228 patients with metastatic lung adenocarcinoma were analyzed for EGFR, KRAS, BRAF and PIK3CA mutations detected by xTAG liquidchip technology (xTAG-LCT), as well as ERCC1, TYMS, RRM1, TUBB3, STMN1, TOP2A and VEGFR1-3 mRNA expression detected by branched DNA-liquidchip technology (bDNA-LCT).

RESULTS: Higher rates of low ERCC1 (35.6 vs. 20.3%, P = 0.0105), RRM1 (23.3 vs. 13.0%, P = 0.0437), STMN1 (72.2 vs. 42.8%, P = 0.0000) and high VEGFR2 (34.4 vs. 18.8%, P = 0.0078) mRNA expression were found in EGFR-mutated tumors, suggesting possible benefit from platinum, gemcitabine, taxanes or VEGFR2 inhibitors. Primary lesions showed low ERCC1 (31.6 vs. 18.5%, P = 0.0271), TYMS (17.6 vs. 7.6%, P = 0.0300), TUBB3 (16.9 vs. 7.6%, P = 0.0415), STMN1 (62.1 vs. 42.9%, P = 0.0065) and high TOP2A (48.7 vs. 33.1%, P = 0.0262) mRNA expression and higher KRAS mutations (25.7 vs. 14.1%, P = 0.0350), suggesting platinum, taxanes, pemetrexed, anti-TOP2A agents and resistant to anti-EGFR therapies. Liver metastases showed absence of low TYMS expression, indicating insensitivity to pemetrexed-based regimen. Pleura metastases harbored higher rates of high VEGFR2 expression (50.0 vs. 19.1%, P = 0.0127). Lymph node metastases presented higher rates of high VEGFR2 expression (37.5 vs. 19.1%, P = 0.0253) and EGFR mutations (59.4 vs. 34.4%, P = 0.0011), suggesting use of anti-VEGFR2 and anti-EGFR therapies.

CONCLUSION: Molecular profiling of 228 lung adenocarcinomas determined a significant difference between biomarkers such as EGFR and KRAS subtypes at primary and metastatic sites. Our results serve as a reference for individual treatment based on different potential targets in metastatic lung adenocarcinoma directed by molecular profiling.