Aberrant gene promoter methylation associated with sporadic multiple colorectal cancer.
BACKGROUND
Colorectal cancer (CRC) multiplicity has been mainly related to polyposis and non-polyposis hereditary syndromes. In sporadic CRC, aberrant gene promoter methylation has been shown to play a key role in carcinogenesis, although little is known about its involvement in multiplicity. To assess the effect of methylation in tumor multiplicity in sporadic CRC, hypermethylation of key tumor suppressor genes was evaluated in patients with both multiple and solitary tumors, as a proof-of-concept of an underlying epigenetic defect.


RESULTS
We examined a total of 47 synchronous/metachronous primary CRC from 41 patients, and 41 gender, age (5-year intervals) and tumor location-paired patients with solitary tumors. Exclusion criteria were polyposis syndromes, Lynch syndrome and inflammatory bowel disease. DNA methylation at the promoter region of the MGMT, CDKN2A, SFRP1, TMEFF2, HS3ST2 (3OST2), RASSF1A and GATA4 genes was evaluated by quantitative methylation specific PCR in both tumor and corresponding normal appearing colorectal mucosa samples. Overall, patients with multiple lesions exhibited a higher degree of methylation in tumor samples than those with solitary tumors regarding all evaluated genes. After adjusting for age and gender, binomial logistic regression analysis identified methylation of MGMT2 (OR, 1.48; 95% CI, 1.10 to 1.97; p = 0.008) and RASSF1A (OR, 2.04; 95% CI, 1.01 to 4.13; p = 0.047) as variables independently associated with tumor multiplicity, being the risk related to methylation of any of these two genes 4.57 (95% CI, 1.53 to 13.61; p = 0.006). Moreover, in six patients in whom both tumors were available, we found a correlation in the methylation levels of MGMT2 (r = 0.64, p = 0.17), SFRP1 (r = 0.83, 0.06), HPP1 (r = 0.64, p = 0.17), 3OST2 (r = 0.83, p = 0.06) and GATA4 (r = 0.6, p = 0.24). Methylation in normal appearing colorectal mucosa from patients with multiple and solitary CRC showed no relevant difference in any evaluated gene.


CONCLUSIONS
These results provide a proof-of-concept that gene promoter methylation is associated with tumor multiplicity. This underlying epigenetic defect may have noteworthy implications in the prevention of patients with sporadic CRC.
Gonzalo
Victoria
V
Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red en el Area temática de Enfermedades Hepáticas y Digestivas, Institut d'investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Catalonia, Spain.
Lozano
Juan José
JJ
Muñoz
Jenifer
J
Balaguer
Francesc
F
Pellisé
Maria
M
Rodríguez de Miguel
Cristina
C
Andreu
Montserrat
M
Jover
Rodrigo
R
Llor
Xavier
X
Giráldez
M Dolores
MD
Ocaña
Teresa
T
Serradesanferm
Anna
A
Alonso-Espinaco
Virginia
V
Jimeno
Mireya
M
Cuatrecasas
Miriam
M
Sendino
Oriol
O
Castellví-Bel
Sergi
S
Castells
Antoni
A
D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000235:genetics*; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D012044:Regression Analysis