COL4A4 and melanoma: Furthermore, we focused on three other cell lines of different origins – A375 (malignant melanoma), HT29 (colon carcinoma) and PC3 (prostatic carcinoma) – where we observed a very similar pattern of morphological changes and downregulation of the genes COL4A4, LAMC2, CTHRC1 and proto‐oncogene WNT7B when the cells were grown in the presence of the anti‐CA I positive serum (SK).