A recent study published in the Journal of Thoracic Oncology focused on the possibility that specific mutations in non-small cell lung cancer (NSCLC) vary according to race. The study was entitled “Racial Diversity of Actionable Mutations in Non–Small Cell Lung Cancer”.
Lung cancer is the primary cause of cancer deaths in the U.S. and worldwide, with cigarette smoking being the main risk factor for the development of the disease. The majority of all lung cancers (85%) are classified as NSCLC and have a higher incidence rate in men then women. Additionally, it seems to affect more black individuals than white, especially within the male gender, however the reason behind this fact remained unknown.
Researchers now suggest that a difference in the frequency of specific cancer gene mutations may explain the higher incidence in black individuals. Genomic research has linked particular oncogenes (genes that have the potential to cause cancer) and respective mutations to the disease phenotype. In this study, the research team designed a large-scale genomic study to analyze 214 specific mutations in 26 different cancer genes in DNA samples of lung cancer patients. All the mutations analyzed had been previously found in NSCLC cases. DNA samples from 472 NSCLC patients were assessed, comprising a total of 137 black and 335 white individuals.
The results showed that in terms of race, the frequency of somatic mutations (i.e., alterations in the DNA of any cell apart from germ cells) in specific NSCLC-linked genes was identical between black and white individuals. However, deletions in the oncogene epidermal growth factor receptor (EGFR) were found to be exclusively present in lung tumors from women, expecially black women. The team suggests that deletions in the EGFR gene can be considered a potential predictive biomarker for the response of patients to anti-EGFR therapy and that, especially women, should be tested for these specific mutations.
Interestingly, another particular EGFR mutation, that had previously been identified as inherited, was found in both normal and malignant tissues from a single patient within the cohort. In addition, two variants of the DDR2 gene, which have been previously identified as activating mutations in NSCLC, were also found in both normal and tumor tissues of some patients. Nonetheless, the particular role of these mutations in lung cancer are still unknown.
The authors suggest that further studies are required to determine NSCLC molecular signatures in different patient populations and that genomic testing of tumors could be advantageous. Inherited alleles should also be further investigated as they may play a role in lung cancer development.