Salmonella typhimurium A1-R exquisitely targets and arrests a matrix-producing triple-negative breast carcinoma in a PDOX model

Background/Aim: Triple-negative matrix-producing breast carcinoma (MPBC) is rare, recalcitrant, and highly aggressive. The present study aimed to determine the efficacy of tumor-targeting leucine-arginine auxotroph Salmonella typhimurium (S. typhimurium) A1-R on a triple-negative MPBC in a patient-derived orthotopic xenograft (PDOX) model. Materials and Methods: The PDOX MPBC model was established in the left second mammary gland of nude mice by surgical orthotopic implantation (SOI). PDOX models were randomized into two groups when the tumor volume reached over 70 mm³: a control group (n=6); and a tumor-targeting S. typhimurium A1-R group (n=7), [intravenous (i.v.) injection of S. typhimurium A1-R via the tail vein, weekly, for two weeks]. All mice were sacrificed on day 14. Tumor volume and body weight were measured once per week. Results: S. typhimurium A1-R exquisitely targeted and arrested the growth of the MPBC PDOX compared to the control group (p=0.017). Conclusion: S. typhimurium A1-R has future clinical potential for triplenegative MPBC patients.