Predictive Role of TP53, PIK3CA and MLL2 in ER+ HER2+ Breast Bancer: Biomarker Analysis of Neo-ALL-IN [NCT 01275859].
Anticancer Res 2020;
40:5883-5893. [PMID:
32988919 DOI:
10.21873/anticanres.14608]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM
Somatic mutations were investigated in 21 patients with postmenopausal estrogen receptor (ER)-positive and human epidermal growth factor receptor-2 (HER-2)-positive (ER+HER2+) breast cancer (BC) treated with neoadjuvant letrozole and lapatinib, to identify their distinct molecular landscape.
PATIENTS AND METHODS
We used tissue samples of 21 patients from phase II Neo ALL-IN cohort, and somatic alterations were examined using targeted exome sequencing performed in Foundation Medicine, Inc. (FMI).
RESULTS
TP53 (61.9%) and PIK3CA (57.1%) were the two most frequently mutated genes that were inter-correlated (p=0.026). They were associated with unfavorable clinical outcomes, particularly when accompanying PIK3CA mutations at exon 9 in helical domains. Meanwhile, MLL2 alteration was negatively associated with mutations of TP53 or PIK3CA, and it tended to be present in patients with low KI-67 levels and no initial nodal involvement. Moreover, patients with MLL2 mutations numerically showed more favorable overall response rates (ORR) (80% vs. 56.2%) and better 5-year event-free survival (EFS) rates (100% vs. 87.5%) compared to the wild-type.
CONCLUSION
Mutations in TP53 and PIK3CA hotspot at exon 9 may be potential negative predictors of ER+HER2+ BC treated with neoadjuvant letrozole and lapatinib, while MLL2 inactivating mutation might confer therapeutic benefit in these patients.
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