Ductal adenocarcinoma of the pancreas usually retained SMAD4 and p53 protein status as well as expression of epithelial-to-mesenchymal transition markers and cell cycle regulators at the stage of liver metastasis.

There are limited data on the biology of metastatic pancreatic ductal adenocarcinoma (PDAC). The aim of the present study was to compare the expression of immunohistochemical markers that may be involved in the development of metastatic disease in primary PDAC and in synchronous liver metastatic tissues. Thirty-two stains (corresponding to proteins encoded by 31 genes: SMAD4, TP53, ACTA2, CDH1, CDKN1A, CLDN1, CLDN4, CLDN7, CTNNB1, EGFR, ERBB2, FN1, KRT19, MAPK1/MAPK3, MAPK14, MKI67, MMP2, MMP9, MUC1 (3 antibodies), MUC5AC, MUC6, MTOR, MYC, NES, PTGS2, RPS6, RPS6KB1, TGFB1, TGFBR1, VIM) were evaluated using tissue microarray of 26 pairs of primary PDACs and their liver metastases. There were no significant differences in expression levels of examined proteins between primary and secondary lesions. In particular, metastatic PDAC retained the primary tumour's SMAD4 protein status in all and p53 protein status in all but one case. This surprising homogeneity also involved expression levels of markers of epithelial-to-mesenchymal transition as well as cell cycle regulators studied. In conclusion, the biological profiles of primary PDACs and their liver metastases seemed to be similar. Molecular alterations of PDAC related to a set of immunohistochemical markers examined in the present study were already present at the stage of localized disease.