Immunohistochemical status of p53, mdm2 and Ki-67 in malignant fibrous histiocytoma.
The aim of the study was to evaluate the frequency of p53, mdm2 and Ki-67 immunopositivity in MFH, and to investigate possible associations of their expression with the grade of malignancy and predominant histological pattern--storiform, pleomorphic and myxoid subtype of MFH. A total number of 51 tumor samples from 21 primary and 30 secondary MFHs was studied using monoclonal anti-p53 (DO-78, DAKO), anti-mdm2 (1F2, NOVOCASTRA) and polyclonal anti-Ki-67 (DAKO) antibodies. The p53 immunopositivity was observed in 32.7% of all tumor samples (in 36.8% of primary and in 30% of recurrent and metastatic tumors). The mdm2 immunopositivity was noted in 34.8% of all tumor samples (in 33.3% of primary and 35.7% of secondary tumors). The mean percentage of p53, mdm2 and Ki-67 positive cells was 15.5, 8.8 and 7.05, respectively. The mean Ki-67 LI was statistically higher in grade 3 than in grade 2 of malignancy (p = 0.006). A significant correlation was found between mdm2 positivity and histological subtypes of MFH--storiform and pleomorphic types were more frequently mdm2 positive than myxoid variant (p = 0.035 and p = 0.009, respectively). No such correlation was observed for p53 positivity of tumors and subtypes, but there was a statistically significant difference in the percentage of p53 positive cells between storiform and myxoid type (p = 0.049). We also noted more tumors expressing high percentage (over 20%) of mdm2 positive cells in pleomorphic and storiform subtypes than in myxoid variant (p = 0.048). The Ki-67 LI was also higher in pleomorphic than in other types of MFH (p = 0.012). A strong positive correlation was found between p53 positivity and mdm2 positivity of tumors in primary MFHs (p = 0.00146). p53 and mdm2 positive tumors were mainly in grade 3 of malignancy, but no statistically significant correlations were noted. A positive correlation between the percentage of p53 positive cells and Ki-67 positive cells (p = 0.0028) was observed.
Szadowska
A
A
Department of Tumor Pathology, Medical University, Lódź.
Olborski
B
B
Harezga-Bal
B
B
Debiec-Rychter
M
M
D018219:Histiocytoma, Benign Fibrous / Q000737:chemistry* / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis*; D009363:Neoplasm Proteins / Q000032:analysis*; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins / Q000032:analysis; D051736:Proto-Oncogene Proteins c-mdm2; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2