Galectin-9 levels have been reported to be altered in several cancer types, but the mechanism that regulates the expression of Galectin-9 has not been clarified. Galectin-9 is encoded by the LGALS9 gene, which gives rise to eight mRNA variants. The aims of this study were: (a) to identify the mRNA variants of LGALS9, (b) to characterize CpG methylation and H3K9 and H3K14 histone acetylation at the promoter of the LGALS9 gene, and (c) to characterize the relationship between these modifications and LGALS9 expression level in cervical cancer cells. All mRNA variants were detected in HaCaT (nontumoural keratinocytes) and SiHa cells, and seven were observed in HeLa cells. The promoter region of LGALS9 contains eight CpG dinucleotides. No hypermethylation pattern related to low LGALS9 expression was identified in tumour cells. Chromatin immunoprecipitation analysis demonstrated higher acetylation of H3K9ac and H3K14ac in HaCaT cells, which was related to higher mRNA levels. The presence of the mRNA variants suggests that alternative splicing may regulate the expression of galectin-9 isoforms. The results of this study suggest that histone acetylation, but not promoter CpG methylation, may be involved in the transcriptional regulation of the LGALS9 gene. Cervical cancer (CC) is the second most lethal cancer among women in undeveloped countries [1]. The aetiological agent for this cancer is human papillomavirus (HPV), and persistent infection with some genotypes of HPV has been associated with the development of CC [2].

Purpose Cervical cancer (CC) is the second most frequent cancer in undeveloped countries. Serum biomarkers could be useful for evaluation of the treatment response and as a complementary means to improve diagnosis. The expression of galectin-9 is altered in cancer tissue, and higher concentrations are found in the serum of cancer patients. The objectives of this study were (a) to determine the serum galectin-9 concentration in patients with intraepithelial lesions and CC, (b) to determine if the concentration was related to the clinicopathological characteristics and (c) to determine if the galectin-9 concentration was related to its expression level in tumour tissue. Patients and Methods In all, 222 serum samples from women with different diagnoses, including premalignant lesions and CC, as well as samples from women with normal cytology were included in the study. The serum galectin-9 concentration was determined by ELISA. To evaluate the expression level of galectin-9 in CC tissue, immunohistochemistry was performed in 34 CC biopsy specimens. Results The galectin-9 concentration in the serum of CC patients (8.171 ng/mL) was increased compared with serum from women with normal epithelia (4.654 ng/mL) and those with low-grade (4.806 ng/mL) and high-grade (5.354 ng/mL) intraepithelial lesions (p value < 0.0001). The area under the ROC curve considering the CC group and the control group was 0.882. The optimal cut-off value was ≥6.88 ng/mL, the specificity obtained was 100%, and the sensitivity was 68.2%. In the CC group, the analysis of the clinical stage showed an increase of galectin-9 in the advanced stage IV group. Serum galectin-9 was not related to the level of galectin-9 expression in tissue, which suggests that galectin-9 is not secreted by tumour cells. Conclusion The serum galectin-9 concentration is related to cancer progression, as the level of this protein is higher in patients with advanced-stage disease.

Galectin-4 has been reported to be altered in different cancer types. Its expression changes have been associated with early recurrence and metastasis. In cervical cancer (CC), galectin-4 has not been studied. The aim of the study was to determine the expression level and subcellular localization of galectin-4 in CC tissue and the concentration in the serum of patients with CC. For the analysis of serum levels of galectin-4, an ELISA assay was performed. To assess the expression in cervical tissue, immunohistochemical staining was performed. The results showed that the concentration of galectin-4 in the serum of patients with CC was higher (647.9 pg/ml) than that in the serum of women with normal cytology (382.1 pg/ml). The immunohistochemical analysis of CC samples showed a higher expression in keratinizing tumor than nonkeratinizing tumors and a trend of increased expression in tumors from patients with advanced clinical stage. In normal cervical tissue, galectin-4 was detected in the cytoplasm, and in tumor cells, the presence of galectin-4 was also detected in the nucleus, in both adenocarcinoma and squamous cervical cancer. The increase in serum concentration and different localization in the tumor cells suggest a possible role of galectin-4 in CC development.