Transcriptional and Epimetabolic Profile of Breast Carcinoma With Luminal or HER2+ or Locally Advanced Triple-negative Histotype in Patients With/Without Previous Clinical History of Metabolic Syndrome

Breast cancer (BC) represents the most common cancer disease among women. In Italy, according to the Aiom-Airtum Report "Cancer Numbers 2020," there are an estimated 54,976 new cases in the female population, which represents 30.3 % of all cancers. Although adherence to screening programs has improved in recent years, the diagnosis of locally advanced BC accounts for about 30% of new diagnoses.

Neo-adjuvant therapy (NCT), which is the administration of chemotherapy drugs combined with biologic therapies if indicated, is the gold-standard in the setting of patients with locally advanced BC (1). It allows down-staging of the primary neoplasm so that conservative rather than demolitive surgical treatment can be performed. NCT also allows prognostic evaluation based on the response obtained to the treatment itself. Noteworthy, a large meta-analysis conducted on 11955 patients enrolled in 12 different clinical trials reported a significant correlation between obtaining a pathological complete response (pathological complete response, pCR, i.e., absence of invasive disease in both breast and lymph nodes) and both event-free survival (EFS) and overall survival (OS) in all tumor subtypes, albeit more pronounced for HER-2 positive neoplasms (EFS: HR 0. 39, CI 95% 0.31-0.50; OS: HR 0.34, CI 95% 0.24-0.47) or triple negative (EFS: HR 0.24, CI 95% 0.18-0.33; OS: HR 0.16, CI 95% 0.11-0.25) (2). To date, about 30% of BC patients go on to pCR following NCT (2), thus highlighting the need for further investigation to expand the proportion of these patients who may benefit from long-lasting clinical responses following such therapy. The consideration of a preexisting history of metabolic syndrome might open new avenues in therapeutic and prognostic perspectives.

Despite the numerous drugs currently available for the NCT, classic chemotherapy (CT) represents the most widely used class of drugs. Growing pieces of evidence show that the efficacy of CT depends not only on its ability to directly inhibit or kill malignant cells, but also on features of the tumor microenvironment in term of metabolic alterations, which might influence the anti-tumoral response (3). Specifically, tumor cell death promoted by cytotoxic drugs causes the release of cancer-associated antigens that, in turn, activate and recruit immune cells within the tumor (4). A recent Italian phase 2 study, the GIADA trial, showed that the number of tumor-infiltrating lymphocytes is significantly associated with pCR and that anthracycline-based chemotherapy treatment results in the establishment of a more immunogenic tumor microenvironment (5). Early results show that despite an improvement in pCR, a considerable number of treated individuals still do not respond or lack long-term responses (6). This evidence suggests that such combinatorial regimens often fail to neutralize all of the immunosuppressive activities that BC enacts to resist CT, evade the anti-tumor immune response, and progress (7). To date, the identification of a system that can predict responses to NCT and the delineation of mechanisms of immunosuppressive resistance in patients with BC unresponsive to NCT remain unresolved issues.

The complex network of interactions between immune cells and other components of the tumor microenvironment results in significant heterogeneity in clinical practice to the response to precision medicine therapeutic options. Consequently, it will be increasingly important to decipher the functional status of the metabolic status of the tumor microenvironment in each patient in order to move from standardized therapy to individualized treatment that in the future could increase survival and improve the quality of life of a greater numbers of BC patients.