In our study, the expression of CYP1B1 by itself does not seem to be predominantly involved in cell proliferation, tumour growth, cell motility or acquisition of an epithelial or mesenchymal phenotype: the cells infected with the wild-type form of the CYP1B1 cDNA present only slight differences with those infected with the empty virus (which have no detectable CYP1B1 expression). The gene discussed is CYP1B1; the disease is neoplasm.