Role of the mitogen-activated protein kinase and phosphoinositide 3-kinase/AKT pathways downstream molecules, phosphorylated extracellular signal-regulated kinase, and phosphorylated AKT in colorectal cancer-a tissue microarray-based approach

Hum Pathol. 2006 Aug;37(8):1022-31. doi: 10.1016/j.humpath.2006.03.002. Epub 2006 May 26.

Abstract

Tumor budding is defined as dedifferentiated cancer cells at the invasive margin of colorectal cancer (CRC) and correlates with a worse prognosis. The invasive margin and tumor budding are normally not present in a superficial diagnostic biopsy specimen. The aim of this study was to investigate the expression/overexpression of 2 downstream molecules of the mitogen-activated protein kinase and phosphoinositide 3-kinase/AKT pathways, phosphorylated AKT (pAKT) and phosphorylated extracellular signal-regulated kinase (pERK), in areas of CRC away from the invasive margin and determining if these variables were predictive of tumor budding or prognosis. A series of 1420 unselected, nonconsecutive CRC resections were subdivided into 3 groups: (1) DNA mismatch repair (MMR) proficient, (2) MLH1-negative, and (3) presumed HNPCC. Immunohistochemical analysis of pAKT and pERK expression (0% versus > 0%) and overexpression (increasing percentage of positivity) was performed using the tissue microarray technique. The results were correlated with clinicopathologic parameters. Fifty-seven samples of normal colon mucosa were included as a control group. Nuclear pERK expression (P = .008) was associated with presence of tumor budding in the MMR-proficient, but not in the MLH1-negative and presumed-HNPCC groups. In contrast, cytoplasmic pAKT overexpression was associated with early T stage (P = .04), early N stage (P = .02), and absence of tumor budding (P = .03) only in the MLH1-negative group. There was no association between pERK or pAKT and clinicopathologic parameters in the HNPCC group. Dysregulation of the mitogen-activated protein kinase pathway is likely to be implicated in the mechanism of tumor budding only in MMR-proficient CRC, whereas the phosphoinositide 3-kinase/AKT pathway is associated with early stage in MLH1-negative CRC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / enzymology*
  • Adenocarcinoma / secondary
  • Aged
  • Biomarkers, Tumor / metabolism
  • Cell Nucleus / metabolism
  • Cell Nucleus / pathology
  • Colon / metabolism
  • Colorectal Neoplasms / enzymology*
  • Colorectal Neoplasms / pathology
  • Extracellular Signal-Regulated MAP Kinases / metabolism*
  • Female
  • Fluorescent Antibody Technique, Indirect
  • Humans
  • Immunoenzyme Techniques
  • Male
  • Middle Aged
  • Mitogen-Activated Protein Kinases / metabolism*
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphorylation
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Tissue Array Analysis / methods

Substances

  • Biomarkers, Tumor
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-akt
  • Extracellular Signal-Regulated MAP Kinases
  • Mitogen-Activated Protein Kinases