Goedert et al. conducted a study in postmenopausal BC women (stages 0–1) and found that these patients showed decreased richness and α-diversity in their fecal microbiota with lower Dorea and Lachnospiracea and higher Clostridiaceae and Faecalibacterium. Of note, the richness was even lower in IgA-positive patients compared with IgA-negative patients. The gene discussed is CD79A; the disease is breast cancer.