In breast cancer tissue, the presence of F nucleatum significantly reduces T cell infiltration, diminishing their ability to combat cancer cells, thus promoting the growth and metastasis of breast cancer.[15] The number of bacteria within tumors shows a negative correlation with T cell infiltration.[68,69] In gastric cancer tissue, the presence of Methylobacterium impairs the function of CD8 tissue-resident memory cells, accelerating tumor development.[70]. Here, CD8A is linked to breast carcinoma.