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 Lea, sialyl Lea, Lex 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 Lex-expressing tumours had more advanced cancer than those with nonsialyl Lex-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 L(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.