COL4A6 and breast cancer: SOX11, PLK1, BUB1, OGN, COL4A6, AGTR1, and ADRB2 may be involved in the recurrence of Basal-subtype breast cancer, and to some extent the PLK1, BUB1, OGN, COL4A6, AGTR1, and ADRB2 can be used as the specific prognostic markers for Basal-subtype breast cancer.