Recently, it has been shown that in triple-negative breast cancer (TNBC) both the molecular and mechanical components (stiffness) of the tumor-associated ECM (tECM) are capable to inhibit the tumor mass permeabilization by cytotoxic CD8+ T cells, whose presence close to cancer is generally associated with good prognosis and successful pharmacological therapy [17]. The gene discussed is CD8A; the disease is triple-negative breast carcinoma.