MKI67 and chronic lung disease: OS was found to be lower, though not statistically significant but considerable in clinical practice, in patients with a Ki-67 proliferation index of 65% and above, whose primary tumor was located in the right lung, who were in the metastatic stage at the diagnosis, who did not receive adjuvant/palliative chemotherapy, who did not undergo curative surgery, and who had a chronic disease (diabetes mellitus, hypertension, chronic lung disease, chronic heart disease).