Findings from a study of patients with lung squamous cell carcinoma (SCC) from North America and East Asia previously suggested that there were no significant differences in alterations between the 2 cohorts1, supporting the hypothesis that lung SCC, though highly mutated, is homogenous across diverse demographic populations. Data from a study conducted by Cardona et al in Colombian patients with lung SCC has further validated this idea, demonstrating the genomic profile of Colombian patients to be similar to that of North American and Asian patients.2
“These findings further strengthen the notion that lung SCC is a relatively homogeneous malignancy throughout the different demographic groups, in contrast with [lung adenocarcinoma],” Cardona et al stated.
Cardona and colleagues obtained tissue samples from 26 Colombian patients with lung SCC treated in Bogota, Colombia, between January 2010 and June 2016. The investigators collected information about patients’ age, gender, tumor, nodes, and metastases, metastasis sites, and Eastern Cooperative Oncology Group (ECOG) performance status. The samples underwent histological review and were evaluated for PD-L1 expression. Next-generation sequencing (NGS) was performed using the Illumina TruSight Tumor 170 assay (TST-170).
The patients in the study were followed for a median of 15.8 months (95% CI,11.2-19.4). The median patient age was 67 years. Eighteen patients were former smokers; 8 were current smokers. Of the 26 patients, 21 had advanced disease (American Joint Committee on Cancer stage IV) and were given cisplatin or carboplatin plus gemcitabine as first-line therapy. The most common primary site of metastasis besides the lungs and pleura (65.4%) was bone (11.5%).
The authors identified 12 gene mutations in the cohort. This finding, combined with the fact that all participants had a history of smoking, aligns with previous clinical insight suggesting that lung SCC is characterized by a heavily mutated genomic environment that could be related to smoking.3,4
The molecular profiling results revealed that inactivating mutations were highly prevalent in TP53, at 61.5%; PIK3CA, at 34.6%; MLL2, at 34.6%; KEAP1, at 38.4%; and NOTCH1, at 26.9%. The genetic alterations were not found to impact overall survival, progression-free survival, or overall response rate; however, higher levels of PD-L1 expression were observed in patients with TP53 (P = 0.037) and PIK3CA mutations (P = 0.05).2
The authors also compared the genetic profile of the Colombian cohort with those from the 2 prior studies involving patients in North America and East Asia, respectively. The first study was conducted as part of The Cancer Genome Atlas (TCGA) and profiled 178 samples from North American patients with lung SCC. The other study included 104 samples from Korean patients with the disease.