Pituitary neuroendocrine tumours (PitNETs) display significant clinical variability, making the identification of predictive biomarkers a priority. In this context, Silva et al. investigated the role of the chemokine CCL2. It has previously been recognised primarily for mediating immune cell recruitment, but its function in PitNET biology has remained unclear. 

Using a well-characterised cohort of 86 patients with PitNETs, associations were reported between elevated CCL2 expression – quantified by mRNA and immunoreactivity – and clinically relevant parameters; these included larger tumour size, hypopituitarism at diagnosis, persistent disease and treatment complexity. Interestingly, elevated CCL2 mRNA was negatively correlated with CDH1 (E-cadherin) expression, suggesting a potential role in promoting epithelial-to-mesenchymal transition. Additionally, higher CCL2 protein expression correlated positively with increased markers of angiogenesis, such as vessel density and area, independent of macrophage infiltration.

While these findings provide novel biological insights into PitNET aggressiveness, the authors acknowledge that their results represent associative evidence rather than direct causation. They emphasise the need for validation through larger, prospective studies before CCL2 can be confidently used as a predictive biomarker or therapeutic target. Nevertheless, the study is a comprehensive, novel exploration of the potential biological roles of CCL2 beyond immune chemotaxis, providing important new insights into PitNET biology.

Read the full article in Endocrine-Related Cancer 32 e240293 https://doi.org/10.1530/ERC-24-0293