Correlation between expression of cellular retinol-binding protein 1 and its methylation status in larynx cancer

Aims: The authors have previously reported that cellular retinol-binding protein 1 (CRBP1) gene gain and its expression correlated significantly with survival in laryngeal carcinoma patients. The authors hypothesised that inactivation of the CRBP1 gene through CpG methylation is associated with patient status and gene expression. In this work, the authors determine the expression and methylation status of the CRBP1 gene and its correlation with clinical variables of laryngeal carcinoma patients. Methods: The CRBP1 gene methylation promoter was assessed by methylation specific PCR analysis in tissue samples from larynx cancer specimens and its expression was assessed by immunohistochemistry on paraffin embedded tissue using tissue microarray. The results were then compared with the clinical pathological variables and outcome measures. The study included 46 samples from patients with non-metastatic squamous cell carcinoma of the larynx without any previous oncological treatments. Results: Lack of CRBP1 expression was seen in 17 of the 46 laryngeal carcinoma samples, while the remaining 29 samples showed increased expression. Significant associations were found between CRBP1 expression and methylation and patient status. There was a tendency for association in all clinical stages of the disease. CRBP1 gene expression and its unmethylated promoter correlated significantly with survival (p<0.05). Conclusions: An early event of larynx cancer could be CRBP1 expression related to unmethylation of the promoter region. These features could also be associated with good response and survival. The authors hypothesised that increased expression and unmethylated promoter of the CRBP1 gene could be considered as markers for larynx cancer.