Tetranucleotide Repeat Microsatellite Instability in Uterine Cervical Carcinomas

ABSTRACT

BACKGROUND: Elevated levels of microsatellite alterations at selected tetranucleotide repeat regions (EMAST) have been recently described, and they are a distinct type of microsatellite instability (MSI). We investigated the prevalence of EMAST in squamous cell carcinoma (SCC) of the uterine cervix and we determined the correlation between EMAST and the clinicopathologic parameters, HPV infection and the p53 mutation. METHODS: We examined the 3 mono-, 3 di-, and 5 tetranucleotide repeat markers in 47 cases of SCC, and we performed immunohistochemical staining for p53. HPV detection and genotyping was performed using a commercially available HPV DNA chip. RESULTS: Thirteen out of 47 cases (27.7%) were EMAST(+) with at least one of five tetranucleotide repeat markers. However, MSI at mono- and dinucleo- tide markers was noted in only one case (2.1%). EMAST was not related with stage, size, lymph node metastasis, vascular/lymphatic invasion or the depth of invasion. Positive immunostaining for p53 was significantly more common in EMAST(+) tumors than in the EMAST(-) tumors (p=0.04). HPV-infection was positive in 32 cases. EMAST was not correlated with the state of HPV infection state or the HPV genotype. CONCLUSIONS: 27.7% of the invasive SCCs of the uterine cervix exhibited EMAST, and EMAST in the SCC of the uterine cervix was significantly associated with the p53 mutation.