However, few studies have considered the effect of the host itself, especially regarding the functional state of PTEN in the microenvironment of the metastatic target organ, on the ability of the metastatic breast cancer cells to colonize, proliferate, and form metastatic foci in the organ, and the mutual adaptation of cells in the target organ microenvironment and metastatic breast cancer cells. This evidence concerns the gene PTEN and breast carcinoma.