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Spatial and Temporal Control of Murine Melanoma Initiation from Mutant Melanocyte Stem Cells
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Involvement of the Ink4a gene (p16 and p19arf) in murine tumorigenesis

I Orlow1, F Rabbani, L Chin

  • 1Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.

International Journal of Oncology
|June 22, 1999
PubMed

Insights

Genetic alterations in Ink4a and Ink4b genes are crucial for tumor development. Deletion of the Ink4a gene was frequently observed in tumors of Ink4a mice, impacting cell cycle regulation.

Area of Science:

  • Genetics
  • Molecular Biology
  • Oncology

Background:

  • The INK4A and INK4B genes located at 9p21 are critical tumor suppressors.
  • INK4A encodes p16 and p19ARF, while INK4B encodes p14, p15, and p17.
  • Alterations in these genes are implicated in various neoplasms.

Purpose of the Study:

  • To investigate genetic alterations in the Ink4a and Ink4b genes in tumors from Ink4a heterozygous mice.
  • To determine the frequency and nature of these alterations.

Main Methods:

  • Analysis of genetic alterations in Ink4a and Ink4b genes.
  • Examination of tumors arising in Ink4a heterozygous mice.

Main Results:

  • Deletion of the remaining Ink4a allele was identified in 39% (7 of 18) of the tumors.
  • Deletion of exon 1beta of Ink4b was observed in 3 cases, with one showing this as the sole alteration.
  • The most frequent alteration was the deletion of the Ink4a allele.

Conclusions:

  • Deletion of the Ink4a allele is a common event in tumor development in this model.
  • These deletions lead to the inactivation of cell cycle-regulating proteins, involving pRB and p53 tumor suppressor pathways.

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