We aimed to:1) Analyse telomerase reverse transcriptase (TERT) mutations in cutaneous
basal cell carcinoma (CBC) tumours and describe its relationship with intra-tumour enzyme activity and telomere length (TL). 2) Compare TERT activity between tumour and clinically healthy peritumoral skin. 3) Compare TL between CBC and peripheral blood.
A cohort of 45 patients with 50 CBC were included. All tumours were located in the neck, face or scalp. Clinicopathological variables were recorded for each patient and tumour.
TERT mutations were studied by direct sequencing and enzyme activity and TL were measured by qPCR in 44 tumours. TL was also measured in peripheral blood leukocytes in 30 patients. TERT activity was studied for peritumoral clinically healthy skin in 20 CBC.
TERT mutations existed in 72 % of the tumours (with 18% of CBC carrying two mutations), mostly showing the UV signature (C→T and CC→TT).
TERT activity was significantly (p=0,012) higher in tumours (mean=1,2597) than in peritumoral clinically healthy skin samples (mean=0.2672). The enzyme was active in every tumour and very scarce or absent in the healthy skin samples.
Telomeres were significantly (p=0,002) longer in tumour samples (mean=1.2597) than in peripheral blood (mean=0,4575).
TERT UV induced mutations are frequent in CBC. TERT is activated in most CBC, mainly due to activating mutations in TERT although alternate pathways may be involved since it is also active in CBC without TERT mutations.
Telomere length is longer in tumoral tissue than in peripheral blood in patients with CBC.

TELOMERASE REVERSE TRANSCRIPTASE MUTATIONS, ENZYME ACTIVITY AND TELOMERE LENGTH IN CUTANEOUS BASAL CELL CARCINOMA