Polymorphisms of the ICAM-1 exon 6 (E469K) are associated with differentiation of colorectal cancer

The polymorphisms at ICAM-1 exon 4 (G241R) and exon 6 (E469K) were detected by PCR with sequence-specific primers. The relationship between specific genotypes of ICAM-1 and differentiation of CRC was evaluated by the histological grade.We showed only GG genotype of ICAM-1 individuals in either CRC or normal controls. The KK genotype of ICAM-1 K469E was found more frequently than in the controls (P < 0.05). Patients with well-differentiated CRC displayed the KK more frequently than those of poor differentiation (P < 0.05).The findings indicate that polymorphisms of G241R are rare in Chinese population and that KK genotype of ICAM-1 K469E is significantly associated with well differentiation of CRC.Colorectal cancer (CRC) is a common malignant disease around the world. CRC has an extremely poor prognosis owing to insidious symptomatology, late clinical presentation and rapid progression and so lead to poor 5-year disease-free survival [1,2]. CRC is related not only to living habits such as dietary but also to the susceptibility of heredity [3]. Individuals who have first-degree relative with CRC have the increased risk of the CRC compared with those without a family history [4], suggesting that genetic factors contribute to risk for colorectal carcinogenesis [5].The intercellular adhesion molecule-1 (ICAM-1) is a single-chain cell surface glycoprotein that belongs to the immunoglobulin superfamily. It is known that ICAM-1 can be aberrantly expressed in CRC and suppress cancer progression via activation of the host immune surveillance system and prevention of cells from detaching from the primary tumor mass and thus attenuate or eliminate metastasis [6,7]. Two single-base polymorphisms in human ICAM-1 gene have been reported, in exon 4 and 6, changing codons 241(G241R) and 469(K469E), respectively, which are common genetic variations associated with diseases [8]. However, it is not well documented that the association of the ICAM-1 gene polymorphisms with CRC developme