Morphological changes of cultures of MDA‐MB‐231 breast carcinoma cells in the presence of four patient's sera with a high level of autoantibodies against carbonic anhydrase I. (A) A light‐microscope picture of living cells with changed morphology cultivated in patients’ sera: SK, SO, SH, SV and in a control human serum (SL) from a healthy donor negative for anti‐CA I autoantibodies, magnification 100×. (B) Selected genes responsible for adhesion, cytoskeleton and WNT signalling (COL1A1 – alpha‐1 type I collagen, COL4A4 – alpha‐4 type IV collagen, LAMC2 – laminin subunit gamma‐2, KRT14 – keratin 14 type I, CTHRC1 – collagen triple helix repeat containing 1, WNT7B – Wingless‐Type MMTV Integration Site Family, Member 7B) are downregulated in cells cultivated in patients’ sera; reverse transcriptase quantitative PCR.