Abstract: Objective:To study the differential expression of nuclear matrix proteins (NMPs) in normal human breast tis -sue and in breast carcinoma tissue using comparative proteomic methods and to further confirm the up-regulation of Lami-nA/C. Methods:NMPs were extracted from 4 normal human breast tissue samples and 4 breast carcinoma tissue samples. Then NMPs were separated by immobilized pH gradient-based two-dimensional polyacrylamide gel electrophoresis ( 2-DE). Differentially expressed proteins in the protein profiling were analyzed with Image Master software and identified by ma-trix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). A list of the corrected mass peaks was obtained as Peptide Mass Fingerprinting (PMF). The different NMPs were analyzed in the National Center for Biotechnology Information (NCBI) database with Mascot search engine. Differential expression of LaminA/C was assayed by Immunohistochemistry (IHC) and Western blot. Results: Well-resolved, reproducible2-DE profiles of human breast tis -sue were obtained. Average protein spots were 904 ± 58in normal human breast tissue and 944 ± 70in breast carcinoma tis-sue. Of the 27spots analyzed, 12proteins including LaminA/C were successfully identified. The positive rates of LaminA/C in the normal breast tissue samples and in breast carcinoma tissue were ( 15%,3/20) and ( 40%,8/20), respectively, with a statisitical significance ( P<0.05). Western blot analysis showed positive expression of LaminA/C in 10normal breast tissue statistical samples and 10breast carcinoma tissue samples and the ratio of LaminA/C/β-actin was 0.21± 0.13and 0.40±0.13, respectively. The mean intensity of LaminA/C showed a significant difference between normal breast tissue and breast carcinoma tissue (P<0.05). Conclusion:Higher expression of LaminA/C was found in breast cancer tissue. LaminA/C may be useful for distinguishing normal breast tissue from tumor tissue and may play a role in the pathogenesis of breast carcinoma.