Prognostic significance of tumour infiltrating lymphocytes in different molecular subtypes of invasive breast carcinoma

Abstract

Metastasis is the main cause of death from cancer, including breast cancer, so the search for simple and effective prognostic parameters is becoming a priority for researchers. The number of tumor-infiltrating lymphocytes is a proven prognostic factor for triple negative and Her2-positive, but not luminal, molecular subtypes of breast cancer. Possible reasons for the failure of this prognostic parameter for luminal subtypes of breast cancer may be the tumor morphological heterogeneity. Objective: to assess the prognostic significance of the tumor-infiltrating lymphocytes number in the invasive breast carcinoma of a non-specific type (IC NST) of various molecular subtypes, taking into account its morphological heterogeneity. 152 patients with IC NST (T1-3N0-2M0) aged 29 to 75 years were enrolled in the study. The molecular subtype was determined using immunohistochemical analysis of the expression of estrogen and progesterone receptors, Ki-67 and Her2/neu. TILs were assessed in accordance with the recommendations of the International TILs Working Group. It was shown that TILs near the structures of various types is heterogeneous only in patients with the luminal Her2-negative subtype of IC NST. In addition, was found that the development of hematogenous metastases and worse metastatic-free survival in this cohort of patients is associated with a high TILs near solid structures and also depended on Ki-67 level. Thus, TILs near solid structures is a potential prognostic factor for the development of distant metastasis in the luminal Her2-negative and Ki-67 level less 20% subtype of IC NST.