Complementary and Alternative Medicine (CAM) is popularly used among breast cancer patients to improve their quality of life. CAM includes dietary supplements such as Active Hexose Correlated Compound (AHCC®), a cultured mushroom extract shown to positively influence the immune system and cancer. Breast cancer recurrence is believed to be caused by cancer stem cells (CSCs). We postulated that AHCC impacts CSCs epigenetically by targeting miRNA pathways. The effects of AHCC on mammosphere growth were observed in MDA-MB-231, MCF-7, and 4T1 cells. Profiling, RT2-qPCR, and western blot analyses were performed to determine AHCC influence on miRNAs and Tenascin C protein in TNBC cell line MDA-MB-231. Balb/c mice were gavaged with AHCC to examine tumorigenesis effects. Our results demonstrated that AHCC reduced mammosphere growth and cell migration, and upregulated tumor suppressor miR-335 expression in different biological settings. Inhibition of miR-335 increased Tenascin C expression. Consequently, AHCC may influence BCSCs through miRNA pathways.