Low acyl-CoA synthetase 5 expression in colorectal carcinomas is prognostic for early tumour recurrence.

It has been shown that the metabolism of long chain fatty acids is involved in colorectal carcinogenesis. Acyl-CoA synthetases (ACSL) activate free fatty acids by synthesis of acyl-CoA thioesters. ACSL isoform 5 (ACSL5) is involved in enterocytic differentiation and maturation by regulating both pro-apoptotic and anti-proliferative effects. Whilst impaired expression of ACSL5 has been associated with sporadic colorectal carcinogenesis, little is known about ACSL5 as a prognostic factor. Aim of this retrospective study was to characterize the prognostic impact of ACSL5 expression levels in sporadic colorectal adenocarcinomas. A total of 72 patients with a median follow-up of 54 months was included. Using a standardized immunohistochemical approach, colorectal adenocarcinomas with low (n=41; group 1) or high (n=31; group 2) ACSL5 levels were identified. In a one-year follow-up, tumour recurrence was significantly increased in group 1 (p=0.0279). The finding was independent of the TNM- and UICC-stage in the surgical resections. Frequency of lymph node metastasis and mortality was not different between the groups. In a long-time follow-up no differences were found between the ACSL5 groups. The data indicate that ACSL5 could be an independent prognostic factor for early recurrence of sporadic colorectal adenocarcinoma.