CA9 and breast cancer: In this study, the 18 most important genes (TSPYL5, CACTIN, ATP5E, CA9, NUP210, TGFB3, SCUBE2, SLC37A1, ARL4D, ARIH1, OR1F1, PSMD7, ALDH4A1, UBQLN1, PRAME, PHF1, UBE2T, and CROCC) associated with BC metastasis were identified after elastic net feature selection due to its ability to manage both multicollinearity and feature selection efficiently [35].