Lung cancer tumors are biologically different in African Americans and European Americans

By Robyn Boyle, RPh, for MDLinx
Published December 7, 2017

Key Takeaways

Researchers at the National Cancer Institute’s Center for Cancer Research in Bethesda, Maryland, found differences in the genes expressed in non-small cell lung cancers (NSCLCs) in African Americans and European Americans, according to a study published in Clinical Cancer Research. Understanding these differences may lead to more effective treatments and improved outcomes.

Khadijah A Mitchell, PhD, and colleagues reported noticeable differences in lung tumor biology between African Americans and European Americans based on comparative molecular profiling.

“Our study finds that although there are similarities in gene signatures between African Americans and European Americans, there are distinct elements of both the coding and noncoding NSCLC transcriptome that vary between the populations with clinical implications,” the authors explained.

More African Americans than European Americans are diagnosed with lung cancer, even though smoking among African Americans is less prevalent than in European Americans. African Americans are also less likely to be heavy smokers, and more often smoke menthol cigarettes. Even in those who have never smoked, the incidence of lung cancer is higher in African Americans vs people of European descent.

Recent studies have provided clues about differences in tumor biology between African Americans and European Americans in cancers of the breast, endometrium, prostate, and colon, so the authors set out to compare differences in gene expression in tumors of African Americans and European Americans with NSCLC.

Patients from seven Baltimore City hospitals undergoing curative surgery for NSCLC were eligible for participation in the study. Comparative molecular profiling used mRNA and miRNA expression arrays to track differences in paired fresh frozen healthy tissue and lung tumor tissue. These two types of RNA have related, but different, roles inside the cell.

The investigators reported that lung cancers from African Americans and European Americans have population-specific changes in differential gene expression. In addition, a drug response prediction tool revealed that a significant proportion of drug response profiles were population-specific and unique to African Americans or European Americans.

For example, European Americans were sensitive to 53 drugs, including the cytotoxic chemotherapy drug irinotecan, while African Americans were predicted to be resistant to them.

Moreover, lung tumors from African Americans were enriched in stem cell and invasive behavior pathways, while lung tumors from European Americans were enriched in cell cycle, mitosis, and proliferation pathways.

The authors noted that additional studies are needed to evaluate the mechanisms involved and the clinical implications in patients.

“Understanding the racial differences in lung tumor biology between African Americans and European Americans, and accounting for its contribution to therapeutic response, could ultimately help to reduce morbidity and mortality in both populations,” they concluded.

To read more about this study, click here.

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