過氧化氫酵素的基因多型性與大腸直腸癌的關聯性

大腸直腸癌是全世界第三常見的癌症,在台灣地區也有高罹患率.過去文獻已經提出的危險因素包括年齡的增加,性別,發炎性腸道疾病,某些遺傳性條件和大腸直腸癌的家族史,都可能是導致大腸直腸癌的發生,有許多研究證實,單核苷酸多樣性與某些癌症和疾病的產生是有關聯性的。 過氧化氫酶（CAT）是一個被充分研究的酵素,其重要功能在保護細胞免受過氧化氫的毒性作用. 在人類中，過氧化氫酶會影響不同的生理和病理狀況。CAT表現的變化已被發表在許多不同的疾病並且CAT基因多型性也被證明是與不同病理生理狀態，如高血壓，糖尿病和哮喘有相關聯。我們研究的主要目的為探討CAT基因的多型性與大腸直腸癌的關聯性。利用聚合酶連鎖反應 - 限制酶切割片段長度多型性（PCR-RFLP）分析97個大腸癌患者其CAT-21A/ T多型性之等位基因的頻率，接著再與89位年齡相當的對照組(ⅡA，有疾病的風險，N = 51; IIB，無疾病的風險，N = 38)進行統計分析。實驗結果顯示在大腸癌患者的CAT-21 T/T等位基因頻率相較於對照組是顯著性偏低 (2.0%和10.1%，p = 0.02)。另外針對大腸直腸癌實驗組進行CAT-21 A/A同合子等位基因和A/T + T/T基因型頻率與腫瘤分期(p = 0.600)，腫瘤大小(p = 0.747)，近端淋巴轉移(p = 0.340) 和遠處轉移(p = 0.106)相關性研究，結果顯示是沒有差異性的。我們的研究首先提出，在台灣地區的人群中CAT -21T/T SNP與大腸直腸癌的發生是有相關性的。

Colorectal Cancer (CRC) represents the third most common cancer worldwide and is high prevalence in Taiwan region. Several risk factors such as gender the presence of inflammatory bowel disease, certain hereditary conditions and a family history of colorectal cancer have been shown to associate with CRC. Reports indicate that single nucleotide polymorphisms (SNPs) are associated with some cancer and disease, Catalase (CAT) is a well-studied enzyme that plays an important role in protecting cells against the toxic effects of hydrogen peroxide. In human, it has been implicated in different physiological and pathological conditions. Polymorphisms in the CAT gene are shown to be associated with different pathophysiological states including hypertension, diabetes mellitus, and asthma. Recently,-21 polymorphism of Catalase has been identified this variant is associated with various diseases. In this study, we investigate the possible association of Catalase gene 21 polymorphism with colorectal cancer in Taiwan region. Using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP),the allele frequency of CAT-21A/T polymorphism was investigated in 97 patients with colorectal cancer and 89 age matched control ( group IIA, with disease risks, n =51; group IIB, without disease risks, n = 38). The frequency of the CAT-21T/T allele in patients with colorectal cancer was significantly lower than in controls (2.0% vs 10.1%, p = 0.02). In addition, the frequencies of CAT homozygous -21 A/A allele and (A/T+T/T) genotype in CRC groups was not associated with stage (p = 0.600)、tumor size (p = 0.747)、 lymph node metastasis(p = 0.340) and distant metastasis (p = 0.106) . Our study presents preliminary but intriguing data suggesting that CAT-21T/T polymorphism may be associated with CRC in Taiwan.