Expression of Lewis^a, Sialyl Lewis^a, Lewis^x, Sialyl Lewis^x, Antigens as Prognostic Factors in Patients with Colorectal Cancer

Abstract

BACKGROUND: Altered expression of blood group-related carbohydrate antigens such as sialyl Lewis (Le)^x antigen in tumours is associated with tumour progression behaviour and subsequent prognosis. However, the prognostic value of the expression of Le-related antigens in colorectal tumours remains unclear.PURPOSE: To clarify the prognostic value of Le^a, sialyl Le^a, Le^x and sialyl Le^x expression in colorectal carcinomas as prognostic factors after surgery.PATIENTS AND METHODS: Colorectal carcinoma samples from 101 patients with primary colorectal carcinoma who underwent surgical resection were subject to immunohistochemical analyses for Le^a, sialyl Le^a, Le^x and sialyl Le^x expression with the respective monoclonal antibodies.RESULTS: Le^a, sialyl Le^a, Le^x and sialyl Le^x were expressed in 69 (68.3%), 73 (72.3%), 66 (65.4%) and 76 (75.3%) carcinomas, respectively. The patients with sialyl Le^x-expressing tumours had more advanced cancer than those with nonsialyl Le^x-expressing tumours (P=0.0029). The survival time after surgery of patients with Le^x- or sialyl Le^x-expressing tumours was significantly shorter than the survival time of those with non-Le^x- or nonsialyl Le^x-expressing tumours, respectively (P=0.023 and P=0.0001, respectively). Cox’s regression analysis revealed that Le^x and sialyl Le^x expression, separate from stage and histological type, were prognostic variables for patient survival (hazard ratio [HR] for sialyl Le^x-positive expression to sialyl Le^x-negative expression 2.90; HR for Le^x-positive expression to Le^x-negative expression 12.76 in stage I/IV, 0.63 in stage II and 1.69 in stage III).CONCLUSIONS: Le^x expression and sialyl Le^x expression in colorectal carcinomas are each associated with poor prognosis. These variables should be considered in the design of future trials.