The functional relevance and prognostic value of this signature was further exemplified by showing that collagen type VI promoted breast cancer invasiveness and that the expression level of the three genes COL6A1, COL6A2, and COL6A3, encoding the three chains assembling for the functional collagen type VI protein, negatively correlated with breast cancer patient prognosis (120). Here, COL6A2 is linked to breast cancer.