AIM: To explore the existence and distribution of prohibitin (PHB) in nuclear matrix and its co-localization with products of some related genes during the differentiation of human hepatocarcinoma SMMC-7721 cells. METHODS: The nuclear matrix of the SMMC-7721 cells cultured with or without 5 × 10-3 mmol/L hexamethylene bisacetamide (HMBA) was selectively extracted. Western blot was used to analyze the expression of PHB in nuclear matrix; immunofl uorescence microscope observation was used to analyze the distribution of PHB in cell. LCSM was used to observe the co-localization of PHB with products of oncogenes and tumor suppressor genes. RESULTS: Western blot analysis showed that PHB existed in the composition of nuclear matrix proteins and was down-regulated by HMBA treatment. Immunofluorescence observation revealed that PHB existed in the nuclear matrix, and its distribution regions and expression levels were altered after HMBA treatment. Laser scanning confocal microscopy revealed the co-localization between PHB and theproducts of oncogenes or tumor repression genes including c-fos, c-myc, p53 and Rb and its alteration of distributive area in the cells treated by HMBA. CONCLUSION: These data confirm that PHB is a nuclear matrix protein, which is located in the nuclear matrix, and the distribution and expression of PHB and its relation with associated genes may play signifi cant roles during the differentiation of SMMC-7721 cells. AIM: To explore the existence and distribution of prohibitin (PHB) in nuclear matrix and its co-localization with products of some related genes during the differentiation of human hepatocarcinoma SMMC-7721 cells. METHODS: The nuclear matrix of the SMMC-7721 cells cultured Western blot was used to analyze the expression of PHB in nuclear matrix; immunofl uorescence microscope observation was used to analyze the distribution of PHB in cell. LCSM was used to observe the co-localization of PHB with products of oncogenes and tumor suppressor genes. RESULTS: Western blot analysis showed that PHB existed in the composition of nuclear matrix proteins and was down-regulated by HMBA treatment. Immunofluorescence observation showed that PHB existed in the nuclear matrix, and its distribution regions and expression levels were altered after HMBA treatment. Laser scanning confocal microscopy revealed th e co-localization between PHB and theproducts of oncogenes or tumor repression genes including c-fos, c-myc, p53 and Rb and its alteration of distributive area in the cells treated by HMBA. CONCLUSION: These data confirm that PHB is a nuclear matrix protein, which is located in the nuclear matrix, and the distribution and expression of PHB and its relation with associated genes may play signifi cant roles during the differentiation of SMMC-7721 cells.