The efficacy of everolimus was largely independent of the most commonly altered genes or pathways, according to a study of 302 archival tumor specimens from patients with hormone receptor–positive, human epidermal growth factor receptor 2–negative breast cancer. Researchers found:

• Progression-free survival benefit with everolimus was maintained regardless of alteration status of PIK3CA, FGFR1, and CCND1 or the pathways of which they are components.

• Qualitative differences in everolimus benefit were seen between patient subgroups defined by the exon-specific mutations in PIK3CA (exon 20 v 9) or by different degrees of chromosomal instability in the tumor tissues.

Citation: Hortobagyi GN, Chen D, Piccart M, et al. Correlative analysis of genetic alterations and everolimus benefit in hormone receptor–positive, human epidermal growth factor receptor 2–negative advanced breast cancer: results From BOLERO-2. [Published online ahead of print October 26, 2015]. J Clin Oncol. doi: 10.1200/JCO.2014.60.1971.