# Cellular mechanisms of hormone secretion in neuroendocrine tumors: what goes wrong?

## TL;DR

This review explores how hormone secretion goes wrong in neuroendocrine tumors, focusing on cellular and molecular mechanisms.

## Contribution

The paper highlights gene and protein expression changes in the exocytic pathway specific to neuroendocrine tumors.

## Key findings

- Dysfunctional secretory pathways in NETs lead to hormone hypersecretion.
- Modifications in exocytic pathway genes and proteins contribute to deregulated hormone secretion.
- Calcium-regulated exocytosis is a key process disrupted in these tumors.

## Abstract

Neuroendocrine tumors (NETs) constitute a heterogeneous group of neoplasms arising from hormone-releasing cells. Secretion of hormones stored in vesicles occurs through calcium-regulated exocytosis, a process that needs to be tightly controlled to avoid unbalanced levels of hormones. A critical feature shared by most of the NETs is a dysfunctional secretory pathway mainly leading to hypersecretion, which often induces clinical complications. In this review, we focus on the cellular process of hormone exocytosis and discuss the potential molecular mechanisms leading to deregulated hormone secretion in various NETs. Particular attention is paid to expression level modifications for genes and proteins involved in the exocytic pathway in NETs.