Publication-only abstracts (abstract number preceded by an "e"), published in conjunction with the 2019 ASCO Annual Meeting but not presented at the Meeting, can be found online only.
Diverse RB1 mutations and co-occurring molecular alterations in advanced NSCLC.
Metastatic Non-Small Cell Lung Cancer
Lung Cancer—Non-Small Cell Metastatic
2019 ASCO Annual Meeting
J Clin Oncol 37, 2019 (suppl; abstr e20672)
Author(s): Jie Huang, Lun-Xi Peng, Jin-Ji Yang, Yi-Long Wu; Guangdong Lung Cancer Institute, Guangdong Provincial Key Laboratory of Translational Medicine in Lung Cancer, Guangdong Provincial People’s Hospital and Guangdong Academy of Medical Sciences, Guangzhou, China; Guangdong Lung Cancer Inst, Guangzhou, China; Guangdong Lung Cancer Institute, Guangdong Provincial People's Hospital and Guangdong Academy of Medical Sciences, Guangzhou, China
Background: Retinoblastoma transcriptional corepressor 1 (RB1) mutation is strikingly more frequent in non-small cell lung cancer (NSCLC) with SCLC transformation (SCLC-T) than that remain NSCLC. However, NSCLC patients harboring RB1 mutations do not necessarily transform to SCLC. Thus, exploring RB1 mutation frequency and co-occurring genomic alterations is potentially important to understand the SCLC-T mechanism. Methods: We investigated 47 NSCLC pts with RB1 aberrations at our institution. Submitted samples (tissue, plasma, cerebrospinal fluid and pleural effusion) were analyzed using next-generation sequencing across at least 139 genes (139-520). Demographics, molecular features and outcomes were analyzed. Results: Among 47 pts (27F/20M), median age was 58. Twenty (47%) had brain metastases and 7 (15%) underwent SCLC-T. A total of 39 types of RB1 mutations were identified, in which copy number deletion is the most common (40%). RB1 mutations were present from early NSCLC and were detected in 88%(29/33), 82%(9/11), 70%(9/13) and 42% (20/48) of tissue, pleural effusion, CSF and plasma samples, respectively. The most frequent co-occurring alterations were TP53 (100%, 95%) and EGFR (100%, 93%) in both SCLC-T group and non-transformed group. Besides, mutations involving in the PI3K pathway were often detected: PIK3CA (57%, 20%), AKT (43%, 10%), PTEN (14%, 15%), MET (14%, 15%), NTRK1 (14%, 13%). Notably, RB1 also co-occurred with ALK fusion (1/47). Moreover, SCLC-T group harbored significant higher frequency of RB1 mutation compared with non-transformed group. Conclusions: RB1 mutations in NSCLC are associated with a trend toward SCLC-T, and the mechanisms may be increased frequency of RB1 mutations and co-occurring similar molecular alterations to those in SCLC.