Decreased and aberrant nuclear lamin expression in gastrointestinal tract neoplasms

Background-Altered expression of lamins AIC and B1, constituent proteins of the nuclear lamina, may occur during differentiation and has also been rep orted in primary lung cancer. Aims-To examine the expression of these proteins in gastrointestinal neopla sms. Patients-Archival human paraffin wax blocks and frozen tissue from pat ients undergoing surgical resection or endoscopic biopsy. Methods-Immunohistochemistry and western blotting using polyclonal antisera against A type lamins and lamin B1. Results-The expression of lamin AIC was reduced and was frequently undetect able by immunohistochemistry in all primary colon carcinomas and adenomas, and in 7/8 primary gastric cancers. Lamin B1 expression was reduced in all colon cancers, 16/18 colonic adenomas, and 6/8 gastric cancers. Aberrant, c ytoplasmic labelling with both antibodies occurred in some colonic cancers and around one third of colonic adenomas. Cytoplasmic lamin AIC expression was detected in 3/8 gastric cancers. Lamin expression was reduced in gastri c dysplasia, but not intestinal metaplasia, atrophy, or chronic gastritis. Lamin expression was low in carcinomas of oesophagus, prostate, breast, and uterus, but not pancreas. Conclusions-Reduced expression of nuclear lamins, sometimes together with a berrant, cytoplasmic immunoreactivity is common in gastrointestinal neoplas ms. Altered lamin expression may be a biomarker of malignancy in the gastro intestinal tract.