Author/Editor		Ravnik-Glavač, Metka; Berginc, Gašper; Potočnik, Uroš; Golouh, Rastko; Repše, Stanislav; Glavač, Damjan
Title		Methodology for molecular genetic screening of microsatellite unstable colorectal cancer and Lynch syndrome
Translated title		Metodologija za molekularnogenetsko presejanje mikrosatelitno nestabilnega kolorektalnega karcinoma in sindroma Lynch
Type		članek
Source		In: Luzar B, Poljak M, Glavač D, et al, editors. Molekularna diagnostika v medicini. Zbornik 15. spominsko srečanje akademika Janeza Milčinskega, 36. memorialni sestanek profesorja Janeza Plečnika, 1. srečanje Slovenskega društva za humano genetiko z mednarodno udeležbo; 2005 30 nov - 2 dec; Ljubljana. Ljubljana: Medicinska fakulteta,
Publication year		2005
Volume		str. 115-25
Language		eng
Abstract		The main goal of gaining knowledge of human diseases is to transfer as much as possible useful information into clinical applications. Microsatellite instability (MSI) is a phenomenon characterized by small deletions or insertions within short tandem repeats in tumour DNA compared to matching normal DNA. Approximately 15% of all colorectal cancers (CRC) have been found to be microsatellite unstable, while MSI is a characteristic of more than 90% of tumours of patients with Lynch syndrome. Patients with MSI tumours have a favorable prognosis and do not benefit from adjuvant chemotherapy with fluorouracil. In addition, the MSI status of tumours is a prescreening step in the detection of patients with Lynch syndrome. Lynch syndrome is the most common autosomal dominant inherited predisposition for colorectal cancer. Carriers of the mutation have 70-80% lifetime risk of developing Lynch syndrome, so there is a need to determine who of members of a Lynch syndrome family test positive for the presence of the mutation. In a 15-year prophylactic screening project, it was shown that colonoscopy at 3-year intervals of at risk and mutation-positive members of Lynch syndrome families more than halved CRC risk and decreased overall mortality by approximately 65%. We describe here our methodology for molecular genetic screening of newly diagnosed CRC for MSI and Lynch syndrome. We developed a multiplex PCR system with a set of five quasimonomorphic mononucleotide markers and DHPLC analysis for the determination of MSI tumours. Further analysis of these tumours for the methylation status of the MLH1 promoter and subsequent mutational analysis enabled us to identify patients with Lynch syndrome.
Descriptors		COLORECTAL NEOPLASMS MICROSATELLITE REPEATS POLYMERASE CHAIN REACTION