Hong-Xia Tian1, Xu-Chao Zhang1, Jin-Ji Yang1, Wei-Bang Guo1, Zhi-Hong Chen1, Zhen Wang1, Yi-Long Wu2. 1. Medical Research Center, Guangdong Lung Cancer Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China. 2. Medical Research Center, Guangdong Lung Cancer Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China. Electronic address: syylwu@live.cn.
Abstract
OBJECTIVES: To investigate the clinical characteristics of anaplastic lymphoma kinase (ALK) rearrangements and sequence complexity of the ALK fusion gene in Chinese lung cancer patients. METHODS: We prospectively screened ALK rearrangements in 1474 lung cancer specimens, including 1387 cases of non-small cell lung cancer (NSCLC), 54 cases of small cell lung cancer (SCLC), and 33 cases of cancer with lung metastasis from other organs by both standard polymerase chain reaction (PCR) and rapid amplification of cDNA ends (RACE)-coupled PCR. Fifteen cases of ALK-positive RACE-coupled PCR products were transformed into Escherichia coli for molecular cloning and sequenced for complexity analysis. RESULTS: The overall frequency of ALK rearrangements was 5.1% (71/1387) in NSCLC. In 71 positive cases, the coexistence of epidermal growth factor receptor (EGFR) and ALK variations was found in 6 cases (8.5%), and the coexistence of different ALK variants was found in 2 cases (2.8%) (1 case with variants 1 and 9; the other case with variants 3 and 2) by PCR analysis. Furthermore, through sequence cloning analysis of 15 cases of non-selective ALK-positive samples, two cases with variants 1 and 3 harbored the coexistence of three subtypes (variant 1 subtypes: E13; A20, E13del63; A20 and E7E12E13; A20 and variant 3 subtypes: E6; A20, E6ins33; A20 and E3E6; A20). Variant 3a and 3b subtypes were always coexistent and had the same proportion of ALK variant 3 rearrangements. ALK rearrangement was associated with young age, female gender, never-smokers, those with adenocarcinoma, advanced stage, and EGFR mutations. No ALK fusion was detected in 54 cases of SCLC or 33 cases of cancer with lung metastasis from other organs. CONCLUSIONS: The identification of novel ALK variants, the coexistence of EGFR mutations and ALK fusions, the coexistence of ALK variants, and the coexistence of subtypes reveal the diversity and sequence complexity of ALK fusions.
OBJECTIVES: To investigate the clinical characteristics of anaplastic lymphoma kinase (ALK) rearrangements and sequence complexity of the ALK fusion gene in Chinese lung cancerpatients. METHODS: We prospectively screened ALK rearrangements in 1474 lung cancer specimens, including 1387 cases of non-small cell lung cancer (NSCLC), 54 cases of small cell lung cancer (SCLC), and 33 cases of cancer with lung metastasis from other organs by both standard polymerase chain reaction (PCR) and rapid amplification of cDNA ends (RACE)-coupled PCR. Fifteen cases of ALK-positive RACE-coupled PCR products were transformed into Escherichia coli for molecular cloning and sequenced for complexity analysis. RESULTS: The overall frequency of ALK rearrangements was 5.1% (71/1387) in NSCLC. In 71 positive cases, the coexistence of epidermal growth factor receptor (EGFR) and ALK variations was found in 6 cases (8.5%), and the coexistence of different ALK variants was found in 2 cases (2.8%) (1 case with variants 1 and 9; the other case with variants 3 and 2) by PCR analysis. Furthermore, through sequence cloning analysis of 15 cases of non-selective ALK-positive samples, two cases with variants 1 and 3 harbored the coexistence of three subtypes (variant 1 subtypes: E13; A20, E13del63; A20 and E7E12E13; A20 and variant 3 subtypes: E6; A20, E6ins33; A20 and E3E6; A20). Variant 3a and 3b subtypes were always coexistent and had the same proportion of ALK variant 3 rearrangements. ALK rearrangement was associated with young age, female gender, never-smokers, those with adenocarcinoma, advanced stage, and EGFR mutations. No ALK fusion was detected in 54 cases of SCLC or 33 cases of cancer with lung metastasis from other organs. CONCLUSIONS: The identification of novel ALK variants, the coexistence of EGFR mutations and ALK fusions, the coexistence of ALK variants, and the coexistence of subtypes reveal the diversity and sequence complexity of ALK fusions.
Authors: Johannes Noé; Walter Bordogna; Venice Archer; Vlatka Smoljanovic; Magalie Hilton; Ryan Woodhouse; Simonetta Mocci; Shirish M Gadgeel Journal: JTO Clin Res Rep Date: 2022-05-18