Predictive markers in breast cancer

04/2021

MUDr. Zuzana Bielčiková, Ph.D.

Onkologická klinika 1. LF UK a VFN, Praha

SUMMARY

Prognostic and predictive markers are the way to the treatment personalization. Prediction of prognosis is important for stratifying the disease according to the risk of relapse and is a prerequisite for escalation or de-escalation of treatment. In the case of early hormone-sensitive (HR+) breast cancer, multigene assays (MGA) in particular fulfil this role. There are also hopes for the prognostic significance of proliferation activity of the disease (Ki 67) in response to neoadjuvant hormonal therapy. For aggressive subtypes (human epidermal growth factor receptor 2 - positive [HER2+] and triple negative breast cancer [TNBC]), main prognostic markers are the achievement of pathological complete remission and the presence of tumor infiltrating lymphocytes, programmed death ligand 1 (PD L1) also stayed in this category. The only and already established predictive markers of therapy response in early breast cancer remain the estrogen receptor (ER) and HER2. We're slightly better at predicting of therapy response in metastatic breast cancer; to ER and HER2 we can add PD L1 in metastatic TNBC, a mutation in the PIK3CA gene in HR+ cancer, and the presence of mutations in BRCA genes as predictors for inhibitors of PARP Prediction of therapeutic effect is also a prerequisite for improving patient survival and for reducing the toxicity of non-target treatment.

Key words

breast cancer, multigene assays, marker of proliferation Ki-67, tumour infiltrating lymphocytes, PD L1, BRCA mutation, PIK3CA mutation