There is ample evidence that neoadjuvant chemotherapy of breast carcinoma is particularly efficient if the tumor presents signs of either a pre-existent or therapy-induced anticancer immune response. Antineoplastic chemotherapies are particularly beneficial if they succeed in inducing immunogenic cell death, hence converting the tumor into its own therapeutic vaccine. Immunogenic cell death is characterized by a pre-mortem stress response including endoplasmic reticulum stress and autophagy. Based on these premises, we attempted to identify metagenes that reflect an intratumoral immune response or local stress responses in the transcriptomes of breast cancer patients. No consistent correlations between immune- and stress-related metagenes could be identified across several cohorts of patients, representing a total of 1045 mammary carcinomas. Moreover, few if any, of the stress-relevant metagenes influenced the probability of pathological complete response to chemotherapy. In contrast, several immune-relevant metagenes had a significant positive impact on response rates. This applies in particular to a CXCL13-centered, highly reproducible metagene signature reflecting the intratumoral presence of interferon-γ-producing T cells.
Keywords: autophagy; breast cancer; colorectal cancer; endoplasmic stress; immunogenic cell death; tumor-infiltrating lymphocytes.