However, beside these numerous arguments towards a role of DCC as a tumour suppressor gene, various concerns, such as the rarity of point mutations identified in DCC coding sequences, the absence of DCC germline mutations involved in a heritable cancer predisposition or the lack of a tumour predisposition phenotype in mice heterozygous for Dcc inactivating mutations, together with the presence of other known and candidate tumour suppressor genes on chromosome 18q have raised questions about the role of DCC. The gene discussed is DCC; the disease is neoplasm.