Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant endocrine tumor syndrome, caused by inactivating mutations of the MEN1 tumor suppressor gene at 11q13 locus, which predisposes to develop tumors in target neuroendocrine tissues. As the positional cloning and identification of the causative gene in 1997, genetic diagnosis, by the sequencing-based research of gene mutations, has become an important tool in the early and differential diagnosis of the disease. Application of the genetic test, in MEN1 index cases and in first-degree relatives of mutated patients, has been constantly increasing during the last two decades, also thanks to the establishment of multidisciplinary referral centers and specific genetic counseling, and thanks to the wide availability of high throughput instruments for gene sequencing and gene mutation identification. The MEN1 genetic test helps the specific diagnosis of probands, and allows the early identification of asymptomatic carriers, strongly contributing, together with progressions in tumor diagnostic techniques and in pharmacological and surgical therapeutic approaches, to the reduction of morbidity and mortality associated with the syndrome. International clinical guidelines for MEN1 have been drafted by panels of specialists in the field, with the main goal to improve the management of the disease and grant patients a better quality of life. Here, we review main recommendations and suggestions derived by the last published general guidelines in 2012, and by most recent published studies about MEN1 syndrome diagnosis, clinical management, therapeutic approaches and patients’ quality of life.

Several strands of evidence indicate that oestrogens exert a protective role against the development of colon cancer through indirect and direct effects on colonic epithelium. Oestrogen receptor β (ERβ), the predominant ER subtype in human colon, is significantly decreased in colonic tumours compared with normal mucosa suggesting a potential role in the regulation of colon tumour growth.

To investigate this hypothesis we engineered human colon cancer ERα-negative HCT8 cells in order to obtain ERβ protein over-expression. Stably transfected cells were cloned and ERβ expression and functionality were monitored by RT-PCR, Western blotting and transactivation in an assay using oestrogen-responsive reporter constructs.

Over-expression of ERβ inhibited cell proliferation and increased cell adhesion in a ligand-independent manner. Its constitutive activation is possibly due to cross-talk with intracellular signalling pathways, as epidermal growth factor and IGF-I were able to induce ERβ transactivation.

A possible mechanism by which ERβ over-expression inhibits proliferation in HCT8 cells is by modulation of some key regulators of the cell cycle; there is a decrease in cyclin E and an increase in the cdk inhibitor p21CIP1. In fact, flow cytometry analysis provided evidence for blocking of the G1-S phase progression induced by ERβ over-expression. The magnitude of this effect was affected by the level of ERβ expression.

These results provide the first direct evidence that ERβ plays an important role in colon cancer as a regulator of cell proliferation through the control of key cell cycle modulators and arrest in G1-S phase transition. These findings are compatible with the hypothesis that the loss of ERβ expression could be one of the events involved in the development or progression of colon cancer.