hMLH1 promoter hypermethylation is an early event in human endometrial tumorigenesis.

It has recently been suggested that silencing of the hMLH1 gene by promoter hypermethylation is the mechanism underlying the presence of the microsatellite instability (MSI) phenotype in sporadic colon and endometrial carcinomas. To determine whether hMLH1 promoter hypermethylation is a relatively early event in endometrial tumorigenesis we evaluated endometrial hyperplasia (EH) characterized as simple, complex, and atypical (the direct precursor of endometrial carcinoma) for hMLH1 aberrant methylation. In addition, we studied the hMLH1, hMSH2, hMSH3, and hMSH6 promoter methylation and MSI status of those endometrial carcinomas with synchronous hyperplasias and those without them. We found that 11 of 12 (91%) cases of endometrial carcinoma (EC) displaying MSI had hMLH1 promoter hypermethylation, whereas aberrant methylation of any of the other mismatch repair genes was not observed. All 15 cases of EC without MSI were unmethylated at hMLH1. Abnormal methylation of hMLH1 was also present in 8 of 116 (7%) cases of EH and was restricted primarily to the atypical endometrial hyperplasia (AEH) type with coexisting endometrial carcinoma. In this set, half of EH methylated at hMLH1 displayed MSI, whereas none of the unmethylated EH had MSI. Our data suggest that hypermethylation of hMLH1 can be an early event in the pathogenesis of EC, preceding the development of an apparent MSI phenotype in a subset of cases.

[1]  Darryl Shibata,et al.  Ubiquitous somatic mutations in simple repeated sequences reveal a new mechanism for colonic carcinogenesis , 1993, Nature.

[2]  R. Fleischmann,et al.  Mutations of two P/WS homologues in hereditary nonpolyposis colon cancer , 1994, Nature.

[3]  R. Kurman,et al.  The behavior of endometrial hyperplasia. A long‐term study of “untreated” hyperplasia in 170 patients , 1985 .

[4]  P. Wingo,et al.  Cancer statistics, 1997 , 1997, CA: a cancer journal for clinicians.

[5]  S. Merajver,et al.  Clinical and pathological significance of microsatellite instability in sporadic endometrial carcinoma. , 1996, The American journal of pathology.

[6]  M. Esteller,et al.  Detection of clonality and genetic alterations in endometrial pipelle biopsy and its surgical specimen counterpart. , 1997, Laboratory investigation; a journal of technical methods and pathology.

[7]  A. Berchuck,et al.  Mutation of the PTEN tumor suppressor gene in endometrial hyperplasias. , 1998, Cancer research.

[8]  K. Kinzler,et al.  hMSH2 mutations in hereditary nonpolyposis colorectal cancer kindreds. , 1994, Cancer research.

[9]  Manel Esteller,et al.  MLH1 promoter hypermethylation is associated with the microsatellite instability phenotype in sporadic endometrial carcinomas , 1998, Oncogene.

[10]  Yusuke Nakamura,et al.  Mutational Analysis of Mismatch Repair Genes, hMLH1 and hMSH2, in Sporadic Endometrial Carcinomas with Microsatellite Instability , 1996, Japanese journal of cancer research : Gann.

[11]  G. Mutter,et al.  Allelotype mapping of unstable microsatellites establishes direct lineage continuity between endometrial precancers and cancer. , 1996, Cancer research.

[12]  J. Herman,et al.  Alterations in DNA methylation: a fundamental aspect of neoplasia. , 1998, Advances in cancer research.

[13]  Robin J. Leach,et al.  Mutations of a mutS homolog in hereditary nonpolyposis colorectal cancer , 1993, Cell.

[14]  D. Ward,et al.  Mutation in the DNA mismatch repair gene homologue hMLH 1 is associated with hereditary non-polyposis colon cancer , 1994, Nature.

[15]  M. Inoue,et al.  K-ras activation in premalignant and malignant epithelial lesions of the human uterus. , 1991, Cancer research.

[16]  D. Shibata,et al.  Microsatellite instability in sporadic endometrial carcinoma. , 1994, Journal of the National Cancer Institute.

[17]  G. Aquilina,et al.  Mismatch Repair Defects andO 6-Methylguanine-DNA Methyltransferase Expression in Acquired Resistance to Methylating Agents in Human Cells* , 1997, The Journal of Biological Chemistry.

[18]  S. Brown,et al.  The precursors of endometrial carcinoma. , 1979, American journal of obstetrics and gynecology.

[19]  R. Kolodner,et al.  Structure of the human MLH1 locus and analysis of a large hereditary nonpolyposis colorectal carcinoma kindred for mlh1 mutations. , 1995, Cancer research.

[20]  A. Berchuck,et al.  Genetic instability of microsatellites in endometrial carcinoma. , 1993, Cancer research.

[21]  X. Matías-Guiu,et al.  Microsatellite instability in endometrial carcinomas: clinicopathologic correlations in a series of 42 cases. , 1998, Human pathology.

[22]  G. Mutter,et al.  Uteri of women with endometrial carcinoma contain a histopathological spectrum of monoclonal putative precancers, some with microsatellite instability. , 1996, Cancer research.

[23]  Kathleen R. Cho,et al.  Microsatellite instability in endometrial carcinoma. , 1994, Oncogene.

[24]  J. Herman,et al.  Inactivation of glutathione S-transferase P1 gene by promoter hypermethylation in human neoplasia. , 1998, Cancer research.

[25]  S. Thibodeau,et al.  Absence of mutations in DNA mismatch repair genes in sporadic endometrial tumors with microsatellite instability. , 1996, Clinical cancer research : an official journal of the American Association for Cancer Research.

[26]  R. Fleischmann,et al.  Mutation of a mutL homolog in hereditary colon cancer. , 1994, Science.

[27]  J. Herman,et al.  Hypermethylation of the hMLH1 gene promoter in human gastric cancers with microsatellite instability. , 1999, Cancer research.

[28]  J. Herman,et al.  Methylation-specific PCR: a novel PCR assay for methylation status of CpG islands. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[29]  K. Kinzler,et al.  Clues to the pathogenesis of familial colorectal cancer. , 1993, Science.

[30]  S N Thibodeau,et al.  Microsatellite instability in cancer of the proximal colon. , 1993, Science.

[31]  G. Thomas,et al.  BAT-26, an indicator of the replication error phenotype in colorectal cancers and cell lines. , 1997, Cancer research.

[32]  S N Thibodeau,et al.  Hypermethylation of the hMLH1 promoter in colon cancer with microsatellite instability. , 1998, Cancer research.

[33]  L. Hedrick,et al.  Mutations in DNA mismatch repair genes are not responsible for microsatellite instability in most sporadic endometrial carcinomas. , 1995, Cancer research.

[34]  L. Kasturi,et al.  Biallelic inactivation of hMLH1 by epigenetic gene silencing, a novel mechanism causing human MSI cancers. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[35]  J. Herman,et al.  Inactivation of the DNA repair gene O6-methylguanine-DNA methyltransferase by promoter hypermethylation is a common event in primary human neoplasia. , 1999, Cancer research.

[36]  J. Palazzo,et al.  MLH1 promoter methylation and gene silencing is the primary cause of microsatellite instability in sporadic endometrial cancers. , 1999, Human molecular genetics.

[37]  P. Hornsby,et al.  Rapid analysis of DNA methylation using new restriction enzyme sites created by bisulfite modification. , 1996, Nucleic acids research.

[38]  J. Herman,et al.  Incidence and functional consequences of hMLH1 promoter hypermethylation in colorectal carcinoma. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[39]  H. Lynch,et al.  Extracolonic cancer in hereditary nonpolyposis colorectal cancer , 1993 .

[40]  R. Levine,et al.  PTEN mutations and microsatellite instability in complex atypical hyperplasia, a precursor lesion to uterine endometrioid carcinoma. , 1998, Cancer research.

[41]  M. Loda,et al.  Methylation of the hMLH1 promoter correlates with lack of expression of hMLH1 in sporadic colon tumors and mismatch repair-defective human tumor cell lines. , 1997, Cancer research.

[42]  Y. Nakamura,et al.  Microsatellite instability in endometrial carcinomas: Frequent replication errors in tumors of early onset and/or of poorly differentiated type , 1995, Genes, chromosomes & cancer.

[43]  N. Copeland,et al.  The human mutator gene homolog MSH2 and its association with hereditary nonpolyposis colon cancer , 1993, Cell.

[44]  J. Boyd,et al.  Causes and consequences of microsatellite instability in endometrial carcinoma. , 1999, Cancer research.

[45]  S. Leung,et al.  hMLH1 promoter methylation and lack of hMLH1 expression in sporadic gastric carcinomas with high-frequency microsatellite instability. , 1999, Cancer research.

[46]  K. Kinzler,et al.  Mutations of GTBP in genetically unstable cells. , 1995, Science.

[47]  P. Goodfellow,et al.  Mutational analysis of MLH1 and MSH2 in 25 prospectively‐acquired RER+ endometrial cancers , 1997, Genes, chromosomes & cancer.

[48]  T Takahashi,et al.  Prognostic significance of p53 mutations and 3p deletions in primary resected non-small cell lung cancer. , 1993, Cancer research.

[49]  E Gabrielson,et al.  Aberrant methylation of p16(INK4a) is an early event in lung cancer and a potential biomarker for early diagnosis. , 1998, Proceedings of the National Academy of Sciences of the United States of America.