Metallothionein - immunohistochemical cancer biomarker: a meta-analysis

Metallothioneins and digestive system tumors

Metallothioneins (MTs) are low-molecular weight, cysteine-rich, intracellular metal-binding proteins involved in diverse functions, such as metal homeostasis and/or detoxification, scavenging free radicals and stress response. Recent studies show that MTs play an important role in cell differentiation, proliferation and carcinogenesis by displaying different expression patterns and through different signaling pathways, have important value for the clinical diagnosis, treatment and prognosis of tumors, and can be used as a cancer biomarker. This article aims to discuss the research progress in MTs as a cancer maker in human digestive system tumors.

Genetic polymorphism of metallothionein 2A and risk of laryngeal cancer in a Polish population

Metallothioneins are intracellular regulators of many biological mechanisms including differentiation, proliferation, angiogenesis and invasion, which are crucial processes in carcinogenesis. This study examines the association between three single-nucleotide polymorphisms at loci -5 A/G (rs28366003) and -209 A/G (rs1610216) in the core promoter region and at locus +838 C/G (rs10636) in 3'UTR region of the metallothionein 2A (MT2A) gene with squamous cell laryngeal cancer (SCLC) risk, as well as with tumor invasiveness according to tumor front grading (TFG). Genotyping was performed using the polymerase chain reaction-restriction fragment length polymorphism technique in 323 genetically unrelated individuals with SCLC and 418 randomly selected healthy volunteers. Only one SNP (rs28366003) was significantly related to laryngeal cancer in the study population. Compared with homozygous common allele carriers, heterozygous and homozygous for the G variant had significantly increased risk of SCLC [adjusted odds ratio (OR) = 2.90, 95 % confidence interval (CI) 1.53-5.21, p dominant < 0.001]. The A/G allele carriers at rs28366003 MT2A were at higher risk of SCLC development (OR = 2.63, 95 % CI 1.41-2.85, p < 0.001]. There was a significant association between the rs28366003 and stage and TFG classification. Most carriers of minor allele had a higher stage (OR = 2.76, 95 % CI 1.11-7.52, p = 0.03), increased cancer aggressiveness, as defined by a higher total TFG score (>18 points) (OR = 3.76, 95 % CI 1.15-12.56, p = 0.03) and diffuse tumor growth (OR = 5.86, 95 % Cl 0.72-44.79, p = 0.08). The results of this study raise a possibility that a genetic variation of MT2A may be implicated in the etiology of laryngeal cancer in a Polish population.