Expression patterns of aquaporin 1 in vascular tumours

Aquaporins (AQPs) are a family of water channels expressed in various body tissues. Beyond osmotic balance, AQPs have recently been confirmed to be involved in processes related to cancer (tumour proliferation, angiogenesis, etc.).

To analyse the presence of these proteins in the endothelium of several vascular tumours, both benign and malignant, in order to establish whether AQPs may be used as a marker or future therapeutic target.

We studied AQP1 expression in 39 patients with vascular tumours, classified into six groups according to ISSVA classification: haemangiomas, benign vascular tumours different from infantile haemangiomas, angiosarcomas, classic Kaposi's sarcoma (KS), and epidemic KS.

AQP1 expression was present in 28 of 39 patients, representing 92.9% benign lesions, whereas no expression was found in 72% of malignant lesions. AQP1 expression was associated with benign lesions with an OR of 34.5 (95% CI: 5-250); p<0.0005, and was most frequently identified with a focal endothelial pattern (38%). A kappa index of 0.823 (95% CI: 0.678-0.971) was determined regarding the patterns of expression overall.

The expression of AQP1 was greater in benign lesions than malignant lesions and this difference was statistically significant, thus AQP1 expression could serve as a marker for benignity of vascular tumours. In addition, the expression pattern of AQP1 was different according to the type of vascular tumour.