Related Experiment Video

Updated: Jun 23, 2026

Three-dimensional Alginate-bead Culture of Human Pituitary Adenoma Cells
08:31

Three-dimensional Alginate-bead Culture of Human Pituitary Adenoma Cells

Published on: February 18, 2016

Expression of p18(INK4C) is down-regulated in human pituitary adenomas

M Golam Hossain1, Takeo Iwata, Noriko Mizusawa

  • 1Department of Medical Pharmacology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.

Endocrine Pathology
|April 30, 2009
PubMed

Insights

Loss of p18(INK4C) expression is common in human pituitary tumors, suggesting its role in pituitary adenoma development. Further research is needed to understand this cell cycle regulator

Area of Science:

  • Oncology
  • Cell Biology
  • Endocrinology

Background:

  • Cyclin-dependent kinase inhibitors (INK4 family) regulate the cell cycle and are often aberrant in cancer.
  • Mice lacking p18(Ink4c) develop pituitary adenomas, indicating its potential role in pituitary tumorigenesis.

Purpose of the Study:

  • To investigate the role of p18(INK4C) in the pathogenesis of human pituitary tumors.
  • To analyze p18(INK4C) expression, gene promoter methylation, and mutations in pituitary adenomas.

Main Methods:

  • Immunohistochemistry to assess p18(INK4C) protein levels.
  • Real-time reverse transcription-polymerase chain reaction for p18(INK4C) mRNA quantification.
  • Analysis of p18(INK4C) gene promoter methylation and somatic mutations.

Main Results:

  • p18(INK4C) protein expression was lost or reduced in 64% of pituitary adenomas compared to normal pituitary glands.
  • Low p18(INK4C) mRNA levels were observed in various pituitary adenoma subtypes, correlating with protein levels.
  • No significant promoter methylation or somatic mutations of the p18(INK4C) gene were detected in most pituitary adenomas.

Conclusions:

  • Down-regulation of p18(INK4C) expression is a frequent event in pituitary adenomas.
  • Reduced p18(INK4C) may contribute to the development of pituitary tumors.
  • Further studies are warranted to elucidate the precise mechanisms of p18(INK4C) dysregulation in pituitary tumorigenesis.

Related Concept Videos

Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
Inhibition of Cdk Activity02:34

Inhibition of Cdk Activity

The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
The Retinoblastoma Gene01:20

The Retinoblastoma Gene

Tumor suppressor genes are normal genes that can slow down cell division, repair DNA mistakes, or program the cells for apoptosis in case of irreparable damage. Hence, they play an essential role in preventing the proliferation of damaged cells.
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
Cancer-Critical Genes II: Tumor Suppressor Genes01:05

Cancer-Critical Genes II: Tumor Suppressor Genes

Genes usually encode proteins necessary for the proper functioning of a healthy cell. Mutations can often cause changes to the gene expression pattern, thereby altering the phenotype.
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
Interactions Between Signaling Pathways01:19

Interactions Between Signaling Pathways

Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
Cell Specific Gene Expression01:58

Cell Specific Gene Expression

Multicellular organisms contain a variety of structurally and functionally distinct cell types, but the DNA in all the cells originated from the same parent cells. The differences in the cells can be attributed to the differential gene expression. Liver cells, whose functions include detoxification of blood, production of bile to metabolize fats, and synthesis of proteins essential for metabolism, must express a specific set of genes to perform their functions. Gene expression also varies with...