In situ RNA-RNA hybridisation of phospholipase C beta 3 shows lack of expression in neuroendocrine tumours.

Background: Phospholipase C beta 3 (PLCB3) plays an important role in the signal transduction of the seven transmembrane receptors. The gene is located in the vicinity of the Multiple Endocrine Neoplasia type 1 (MEN1) gene on chromosome 11q13. Transfection of PLCB3 to neuroendocrine cell lines lacking expression suppresses the neoplastic phenotype and affects the gene expression of S100A3 and human mismatch repair protein, suggesting a role for PLCB3 in neuroendocrine tumorigenesis.
Materials and Methods: We used RNA-RNA in situ hybridisation for PLCB3 on a total of 82 samples including 34 from MEN1 patients.
Results: We show that the PLCB3 transcript is missing in 8 out of 14 MEN1-associated neoplasias as well as in 4 out of 10 bronchial carcinoids, 2 out of 10 exocrine pancreatic cancers and one sporadic adrenocortical carcinoma.
Conclusion: Low or lack of PLCB3 expression in a subset of endocrine tumours, together with earlier published in vitro data on suppressor characteristics upon transfection, indicate that PLCB3 could be involved in the tumorigenesis in a subset of endocrine tumours.