In CPC-N cells, which are derived from the chemo-sensible SCLC type of lung cancer, Ki-67 expression was consistently reduced by more than 50% in response to all three drugs; the same holds true for HEK cells (about 90% positively stained tumor cells in medium controls vs. 30 – 40% in the presence of the cytotoxic drugs). This evidence concerns the gene MKI67 and small cell lung carcinoma.