To determine the presence of infiltrating tumor cells in the adjacent brain parenchyma the brain biopsy specimens were immunohistochemically assessed with appropriate labelling for pan-cytokeratin (NSCLC, breast-, kidney and colorectal carcinoma), Melan-A (melanoma) or chromogranin A (SCLC), based on the immune reactivity of the tumor bulk. This evidence concerns the gene CHGA and colorectal carcinoma.