Increased expression of heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP) in pancreatic tissue from smokers and pancreatic tumor cells

Pancreatic cancer is a major cause of deaths in the United States, and has one of the lowest 5-year survival rates. Early diagnosis has not been possible due to the lack of reliable early tumor markers. The heterogeneous nuclear ribonucleoprotein A1/B2 (hnRNP) was recently shown to be up-regulated in the early stage of lung cancer. This protein plays an important role in biogenesis and transport of mRNA. Up-regulation of hnRNP usually precedes morphological differentiation and is considered a good biomarker in the early stages of cancer development. Because smoking is a high risk factor for pancreatic cancer, this study examined the expression of hnRNP in human pancreatic tissues from smokers and non-smokers. A two-fold increase in expression of hnRNP was found overall in smokers when compared to non-smokers and smokers who quit (P<0.05). The increase in expression of hnRNP was higher in female smokers compared to female non-smokers. High levels of expression was also shown in a limited number of human pancreatic adenocarcinomas and two pancreatic tumor cell lines, HPAF-11 and SU 86.86. HP-8, a normal primary pancreatic cell line, did not express hnRNP. These results strongly suggest that up-regulation of hnRNP may be a good candidate for early screening for pancreatic cancer because of its activation in pancreatic tissue from smokers and activation in pancreatic adenocarcinomas. Over-expression of hnRNP has been suggested as evidence that normal transcriptional regulation is altered.