Agnieszka K. Witkiewicz, M.D., from Thomas Jefferson University in Philadelphia, and colleagues used gene expression profiling and histology to examine whether disruption of the RB pathway was associated with the response to neoadjuvant chemotherapy in approximately 1,000 breast cancer patients.

The researchers found that an RB loss gene expression signature was associated with an improved pathological complete response in patients treated with three different chemotherapy regimens, regardless of estrogen receptor status. Increased expression of p16ink4a, a protein in the RB pathway, was associated with the RB-loss of signature, and p16ink4a mRNA levels were associated with pathological complete response. The association of RB loss and elevated p16ink4a with pathological complete response was also observed in an independent cohort.

"These data indicate that RB-status is associated with the response to neoadjuvant chemotherapy in breast cancer and could be employed to inform treatment," Witkiewicz and colleagues conclude.

Abstract
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