Is there a role for epithelial-mesenchymal transition in adrenocortical tumors?

Epithelial-mesenchymal transition (EMT) is a biological dynamic process by which epithelial cells lose their epithelial phenotype and acquire mesenchymal invasive and migratory characteristics. This has been postulated as an essential step during cancer progression and metastasis. Although this is well described in other tumors, the role of EMT in adrenocortical tumors (ACT) has yet to be addressed.

The aim of this study was to evaluate the expression of EMT markers e-cadherin, vimentin, and fibronectin, along with EMT-transcription factors (EMT-TFs), TWIST1, SIP1, and SNAIL in 24 adrenocortical carcinoma (ACC), 19 adrenocortical adenomas (ACA), 27 childhood-onset adrenocortical tumors (CAT), and 12 normal adrenal glands. The association of EMT and EMT-TFs with clinical outcomes and pathology features were also evaluated.

Cytoplasmic vimentin expression was increased among CAT samples when compared to ACC, ACA, and normal adrenal samples (p < 0.001). There was no difference in e-cadherin and fibronectin expression observed between groups. Nuclear and cytoplasmic expression of TWIST1 and SIP1 was stronger in CAT and ACC vs. ACA and normal tissue samples (all, p < 0.05). ACT, regardless of classification, exhibited increased SNAIL expression when compared to normal tissue (p < 0.05). A significant correlation was observed between vimentin and TWIST1 (r _s = 0.44, p < 0.001); SIP1 (r _s = 0.51, p < 0.001); and SNAIL (r _s = 0.23, p < 0.05). TWIST1 and SIP1 expressions demonstrated a significant correlation (r _s = 0.56, p < 0.001). High SIP1 expression was associated with a lower survival rate among ACC cases (p < 0.05).

Vimentin, TWIST1, and SIP1 expressions are increased in aggressive ACT. Therefore, EMT may play a relevant role in adrenal tumorigenesis.