Expression of the tumor suppressor gene hypermethylated in cancer 1 in laryngeal carcinoma

Abstract

Hypermethylated in cancer 1 (HIC1) is a putative suppressor gene, cooperating with TP53 in the regulation of apoptosis. The promoter site of this gene contains CpG islands susceptible to methylation. Altered methylation leads to the silencing of HIC1. Persistent loss of HIC1 function reflects the attenuation of proapoptotic characteristics of TP53 and may constitute the background for carcinogenesis. Altered methylation profiles along with diminished expression of HIC1 were documented in a number of solid neoplasms. The aim of this study was to evaluate the expression of the HIC1 gene in laryngeal carcinoma. RNA was extracted from samples of laryngeal cancer and corresponding healthy tissues of 21 patients with advanced laryngeal cancer (T3-T4). The amount of RNA (cDNA) was evaluated using reverse transcription-quantitative polymerase chain reaction with GADPH as the reference gene. Data demonstrated that HIC1 expression was significantly reduced in laryngeal cancer tissues. The relative expression of HIC1 was found to be ~40% lower in tumor samples compared to that in healthy controls. The median tumor/normal tissue ratio for HIC1 was 0.615. These results suggest that low HIC1 expression may be associated with neoplastic transformation in the larynx.

Keywords: hypermethylated in cancer 1; laryngeal cancer; tumor suppressor gene.

Figure 1.

Relative expression of the hypermethylated in cancer 1 gene in tumor and healthy tissue samples, normalized to the GAPDH reference gene (mean ± standard error).

Figure 2.

Profiles of expression of the hypermethylated in cancer 1 gene in pairs of cancerous and control samples in each of the investigated patients, normalized to the GAPDH reference gene (mean ± standard error).