MAPK8 and familial pancreatic carcinoma: In conclusion, we show that inhibition of ErbB2 and MUC4 expression did not impair the same signalling pathways (inhibition of MUC4 expression affects the JNK pathway whereas that of ErbB2 alters the MAPK pathway) and produced different effects on pancreatic cancer cell biological properties, suggesting independent activity of these two proteins (Figure 6).