The nuclear matrix (NM) is the structural framework of the nucleus that consists of the peripheral lamins and pore complexes, an internal ribonucleic protein network, and residual nucleoli. Differences between the nuclear matrix protein (NMP) composition of transformed cells and their normal homologues were detected in numerous cases. Actually several tumor-specific nuclear matrix proteins (NMPs) are proposed for diagnostic of bladder, breast, colon and some other cancers. According to the role of NMPs in development and phenotype of a given neoplasms the tumors can be classified as follows: I. Tumors bearing mutations in the genes encoding NMPs. The group consists of following subgroups: 1) hereditary cancer syndromes with mutations in the NM-attached oncoproteins or tumor suppressor genes; 2) sporadic tumors with somatic mutations in the NM-attached oncoproteins, tumor suppressor genes or replication enzymes; 3) leukemias with fused NMPs. II. Tumors with phenotypic quantitative or qualitative changes of the NMP spectrum.