CA1 and neoplasm: Further in vitro research on tumour cells showed that treatment with these sera may result in the up‐regulation of the CA1 mRNA expression, which can be linked to the down‐regulation of the mRNAs encoding structural proteins of basal lamina, the cytoskeleton, WNT7B and collagen triple helix repeat containing 1 (CTHRC1).22 On the other hand, CA1 mRNA silencing via the RNA interference system in PC3 tumour cells enhanced the expression of some of the extracellular matrix (ECM) proteins.23