SMAD5 and breast cancer: Moreover, in breast cancer, exosomal long noncoding RNA (lncRNA) SNHG16 has been shown to promote the development of CD73 + γδ1 Treg cells in breast cancer by sequestering miR-16-4p, leading to the suppression of SMAD5, activation of the TGF-b1/SMAD5 pathway, and ultimately increasing CD73 expression [72].