CXCL12 G801A polymorphism is associated with an increased risk of benign salivary gland tumors in the Chinese population.

The chemokine CXCL12 and its receptor CXCR4 have been found to be important in tumor progression. A single-nucleotide polymorphism of CXCL12 G801A has been described and investigated in human immunodeficiency virus-1 (HIV-1) infection and in the susceptibility to several cancers. Here, we investigated the association between the CXCL12 G801A polymorphism and susceptibility to benign and malignant salivary gland tumors (SGTs) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 102 Chinese SGT patients and 101 healthy controls. The frequencies of the AG (P = 0.001; odds ratio (OR), 3.764) and AA (P = 0.004; OR, 6.852) genotypes of CXCL12 were significantly higher in patients with benign SGTs than in the healthy controls. The frequency of the A allele of CXCL12 was also significantly higher in benign SGTs (P = 0.00; OR, 1.395) compared with the healthy controls. However, the AG (P = 0.171; OR, 3.163) and AA (P = 0.854; OR, 0.667) genotypes did not increase the risk of malignant SGTs significantly. The frequency of the CXCL12 A allele was also not found to be higher in malignant SGTs (P = 0.267; OR, 1.917) compared with the controls. Taken together, our results suggested that the CXCL12 G801A polymorphism is associated with an increased risk of benign SGTs, but not malignant SGTs, in the Chinese population.

Cyclin D1 gene polymorphism, A870G, is associated with an increased risk of salivary gland tumors in the Chinese population.

Expression of Cyclin D1 is believed to lead to progression through the G1 to S cell cycle checkpoint, and both experimental and pathological evidence suggests that overexpression of this protein may increase the risk of several cancers. The Cyclin D1 A870G polymorphism may modulate expression of the Cyclin D1 protein and is associated with the development of several types of tumor. We investigated the association between the Cyclin D1 A870G polymorphism and susceptibility to salivary gland tumors (SGTs) by PCR-RFLP in 102 Chinese SGT patients and 101 healthy controls. The frequencies of the AG (p=0.002; odds ratio (OR), 3.466) and AA (p=0.003; OR, 3.133) genotypes of Cyclin D1 were significantly higher in patients with SGT than in the healthy controls. The frequencies of these two genotypes were also significantly higher in pleomorphic adenoma (PA) patients (p=0.002; OR, 2.229), compared with the healthy controls. In addition, the expression of Cyclin D1 was found to be significantly higher in PA patients with the AA genotype, compared with PA patients with the GG genotype. Taken together, our results suggested that the Cyclin D1 A870G polymorphism is associated with an increased risk of SGTs in the Chinese population. The Cyclin D1 AA genotype not only increased the risk of PA, but also increased the expression of Cyclin D1 in this type of tumor.

[Expression of beta-catenin and adenomatous polyposis coli protein and correlation between them in the development of mouse tooth germ].

OBJECTIVE: To examine the distributions of beta-catenin and adenomatous polyposis coli (APC) protein in the tooth germ, and obtain the messages of function of the two factors and the relationship between them. METHODS: Mice were selected and cohabited with the ratio of female mice to male ones being 2:1, and Embryo day 0.5 was confirmed based on the finding of vaginal plug. The distributions of beta-catenin and APC protein in the Embryos on day 13.5, 14.5, 15.5, 16.5, 17.5 were examined in the paraffin-embedded sections by immunohistochemistry methods. RESULTS: During E13.5 d to E17.5 d, positive expression of beta-catenin was found in the oral epithelium and the dental lamina, and became more and more strong. The staining were whole cell. During the bud stage, strong positive expression of APC protein was found in the oral epithelium and the dental lamina, but the expression displayed a down-regulation tendency. The staining was the cytomembrane and cytoplasm. There was negative correlation between beta-catenin and APC protein (P<0.01). CONCLUSION: The result of beta-catenin suggests its contribution in the early development of enamel organ and the proliferation of cell. Coincidance of the two factors staining site was found, according to the statistics.

Abnormal expression of Rb pathway-related proteins in salivary gland acinic cell carcinoma.

Salivary gland acinic cell carcinoma (ACC) is a relatively rare neoplasm, and limited information is available regarding its molecular pathogenesis. Because the deregulation of Rb pathway is common to most human tumors, we immunohistochemically investigated the expression of Rb pathway-related proteins, including Rb, Rb proteins phosphorylated at serine 780 and 795 (pRb-S780 and pRb-S795, respectively), cyclin D1, and p16INK4a in 18 cases of ACC. The expression of topoisomerase II-alpha and Ki-67 was also examined to evaluate cell proliferation. All the ACCs exhibited substantial numbers of positive cells against Rb antibody that recognizes both unphosphorylated and phosphorylated Rb proteins. The numbers of positive cells for pRb-S795 and cyclin D1 significantly increased in ACCs as compared with normal salivary glands. Double immunofluorescent staining demonstrated that pRb-S795 was colocalized with cyclin D1 in most tumor cells. However, neither significant change of the expression of Rb protein phosphorylated at serine 780 nor its colocalization with cyclin D1 was observed. The loss of p16INK4a is infrequent, but its expression was correlated with phosphorylated Rb proteins. Our results suggest that serine 795 but not serine 780 is the preferred phosphorylation site induced by cyclin D1. This phosphorylation appeared to be critical for inactivation of Rb-mediated growth suppression and may play an important role in the pathogenesis of ACC.