When should genetic testing be performed in patients with neuroendocrine tumours?
Multiple endocrine neoplasia (MEN) types 1 and 2 syndromes are rare hereditary cancer syndromes expressing a variety of endocrine and non-endocrine neoplasias and lesions. The improving of both molecular and clinical genetics knowledge helps health care providers in the whole spectrum of the clinical managements of MEN patients. The MEN1 gene, a tumour suppressor gene, is responsible of MEN1 syndrome, and is probably involved in the regulation of several cell functions, including DNA replication and repair and transcriptional machinery. RET proto-oncogene encodes for a receptor tyrosine kinase protein whose expression is fundamental for appropriate migration, development and differentiation of neuroendocrine cells originating from neural crest. Currently, DNA testing makes possible the early identification of germline mutation in asymptomatic mutant gene carriers in both MEN syndromes. Consequently, the combination of new genetic and diagnostic tools could permit a precocious detection of MEN-associated neoplasms, and in particular the identification of a strong genotype-phenotype correlations in MEN2 syndrome demonstrates an improving outcome and quality of life for affected subjects.