African-Americans are as likely to display epidermal growth factor receptor (EGFR) mutations in NSCLC tumors as Caucasians, suggesting they are also as likely to benefit from erlotinib and other targeted therapies, according to data reported at the AACR International Conference on Molecular Diagnostics in Cancer Therapeutics Development.
Previous data suggested that African-Americans had lower rates of EGFR mutation and were therefore less likely to respond to tyrosine kinase inhibitors, said senior author Ramsi Haddad, PhD, Director of the Laboratory of Translational Oncogenomics at the Barbara Ann Karmanos Cancer Institute in Detroit and Assistant Professor at Wayne State University School of Medicine.
The new study contradicts this, Dr. Haddad said, noting that the results also showed that EGFR mutations in NSCLC in African-Americans have an extreme bias towards exon 19 rather than exon 21—100% of EGFR mutations in African-Americans were in exon 19, versus only in two-thirds of the mutations in Caucasian patients—which would result in a better response to EGFR—targeted therapeutics.
Dr. Haddad speculated that the earlier study did not include enough African-Americans overall, and especially not enough African-American non-smokers.
Dr. Haddad's team observed 149 patients with NSCLC, including 80 Caucasians and 69 African-Americans. Examining 238 mutations in 19 oncogenes using the OncoCarta v1.0 molecular diagnostic assay, the researchers identified EGFR mutations in 12 Caucasians and eight African-Americans. The difference was not statistically significant.
The study has immediate implications for treatment planning for African-American NSCLC patients, Dr. Haddad said. If African-Americans with NSCLC harbor mutations in EGFR at rates similar to whites, then “African ancestry should not be a factor when deciding whether to test a tumor for these mutations.”