CA9 and breast carcinoma: Corroborating our findings in the breast cancer cells, CAIX expression was upregulated by PK-8 pancreatic ductal adenocarcinoma cells cultured in hypoxia and CAIX co-IPed with MMP14 in a reciprocal manner from these cells, whereas the association was not readily detected in PK-8 cells grown in normoxia (Supplementary Figures S1c and d).