Independent prognostic role of p16 expression in lung cancer

J Thorac Cardiovasc Surg. 1999 Sep;118(3):529-35. doi: 10.1016/s0022-5223(99)70192-3.


Objectives: The cyclin-dependent kinase p16 (also known as Ink4A, Mts1, Cdkn2, and Cdkn4i) has been proposed as a tumor suppressor gene mapped on chromosome segment 9p21. This study evaluated p16 protein expression in 135 lung cancer specimens and investigated potential genetic alterations occurring in this gene.

Results: We found altered p16 immunohistochemical expression to be a frequent event in lung cancer and to be independent of either the histologic type or any other clinical-pathologic feature. Western blot analyses performed on about one third of the specimens correlated highly with these results. In addition, we found p16 immunohistochemical expression to be a favorable prognostic factor in lung cancer in that its reduction or loss correlated with a worse outcome for the patients. Polymerase chain reaction amplification and direct sequencing of p16 exons 1 and 2 revealed no mutations, indicating that p16-altered expression in lung cancer is not necessarily linked to mutational events of these genes.

Conclusions: We conclude that p16-altered expression is both an independent and frequent event in lung cancer and may have an important role in tumorigenesis and in malignant progression of a significant proportion of these cancers. However, the actual incidence and relevance of p16 mutations in this neoplasm continues to be debated, and its analysis seems inconclusive. Our results suggest a prognostic role for the immunodetection of this protein on formalin-fixed and paraffin-embedded specimens. They further suggest its routine use in the evaluation of the frequently unpredictable behavior of lung cancer.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenocarcinoma / genetics*
  • Adenocarcinoma / metabolism
  • Adenocarcinoma / pathology
  • Blotting, Western
  • Carcinoma, Small Cell / genetics*
  • Carcinoma, Small Cell / metabolism
  • Carcinoma, Small Cell / pathology
  • Carcinoma, Squamous Cell / genetics*
  • Carcinoma, Squamous Cell / metabolism
  • Carcinoma, Squamous Cell / pathology
  • Cyclin-Dependent Kinase Inhibitor p16 / metabolism*
  • DNA, Neoplasm / analysis
  • Exons
  • Female
  • Gene Expression*
  • Genes, p16 / genetics*
  • Humans
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / pathology
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Polymerase Chain Reaction
  • Prognosis


  • Cyclin-Dependent Kinase Inhibitor p16
  • DNA, Neoplasm