Background: Experimental evidence suggests that lung cancer development and progression can be linked to an increased proliferation rate.
Aims/methods: To evaluate the immunohistochemical expression of seven components of the cell cycle machinery in a series of well characterised non-small cell lung cancer (NSCLC) specimens (n = 105).
Results: Multivariate analysis revealed that simultaneous loss of expression of three of these factors--cyclin D1, the cyclin dependent kinase inhibitor p16, and the tumour suppressor retinoblastoma protein Rb2/p130--correlated with survival, confirming the hypothesis that the cyclin D1-p16-retinoblastoma tumour suppressor pathway is inactivated in most lung cancer samples.
Conclusions: These results suggest that loss of control of cell cycle checkpoints is a common occurrence in lung cancer and support the idea that functional cooperation between different cell cycle regulatory proteins constitutes another level of regulation in cell growth control and tumour suppression.