Abstract
Colorectal cancer (CRC) has traditionally been classified into two groups: microsatellite stable/low-level instability (MSS/MSI-L) and high-level MSI (MSI-H) groups on the basis of multiple molecular and clinicopathologic criteria. Using methylated in tumor (MINT) markers 1, 2, 12, and 31, we stratified 77 primary CRCs into three groups: MINT++ (>2), MINT+ (1-2), and MINT- (0 markers methylated). The MSS/MSI-L/MINT++ group was indistinguishable from the MSI-H/MINT++ group with respect to methylation of p16(INK4a), p14(ARF), and RIZ1, and multiple morphological features. The only significant difference between MSI-H and non-MSI-H MINT++ cancers was the higher frequency of K-ras mutation (P < 0.004) and lower frequency of hMLH1 methylation (P < 0.001) in the latter. These data demonstrate that the separation of CRC into two nonoverlapping groups (MSI-H versus MSS/MSI-L) is a misleading oversimplification.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adaptor Proteins, Signal Transducing
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Carrier Proteins
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Colorectal Neoplasms / classification
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Colorectal Neoplasms / genetics*
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Colorectal Neoplasms / pathology*
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Cyclin-Dependent Kinase Inhibitor p16 / genetics
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DNA Methylation
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DNA-Binding Proteins*
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Histone-Lysine N-Methyltransferase
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Humans
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Microsatellite Repeats / genetics*
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MutL Protein Homolog 1
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Neoplasm Proteins / genetics
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Nuclear Proteins / genetics
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O(6)-Methylguanine-DNA Methyltransferase / genetics
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Prospective Studies
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Transcription Factors*
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Tumor Suppressor Protein p14ARF / genetics
Substances
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Adaptor Proteins, Signal Transducing
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Carrier Proteins
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Cyclin-Dependent Kinase Inhibitor p16
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DNA-Binding Proteins
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MLH1 protein, human
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Mlh1 protein, mouse
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Neoplasm Proteins
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Nuclear Proteins
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Transcription Factors
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Tumor Suppressor Protein p14ARF
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Histone-Lysine N-Methyltransferase
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PRDM2 protein, human
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O(6)-Methylguanine-DNA Methyltransferase
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MutL Protein Homolog 1