Tumour infiltrating lymphocytes are a sign of immune mediated reaction of the host against the tumour. They are considered as a positive prognostic marker and may also have a predictive role for the use of certain therapies. The challenge remains to convert tumours with low tumour infiltrating lymphocytes into tumours with high tumour infiltrating lymphocytes in order to enhance the immune mediated effect of therapies.

PIK3Ca mutation is one of the most frequent mutations encountered in breast cancer, particularly in hormone receptor positive cancer in which it can confer resistance to hormonal therapy. Therefore, a lot of effort has been made to target the PI3K-pathway with drugs, and to find a way to predict their efficacy: some results have been achieved; in particular with the detection of PIK3Ca in circulating DNA, but many questions still remain. This article provides an overview concerning these two biomarkers, and attempts to determine whether they could be used in clinical practice today.

(BELG J MED ONCOL 2017;11(1):7–11)