Background: Differential diagnoses of hydatidiform moles from non-molar specimens as well as their sub-classification such as complete and partial hydatidiform moles are important for clinical management and accurate risk assessment for persistent gestational trophoblastic disease, but diagnosis based solely on histomorphology suffers from poor interobserver and intraobserver reproducibility.Objectives: This study was undertaken to determine whether the expression of Ki-67 protein could differentiate these entities.Materials and Methods: We performed Ki-67 immunohistochemical staining in 19 molar (8 partial and 11 complete moles) and 10 non-molar (hydropic abortions) formalin-fixed, paraffin-embedded tissue samples. Ploidy analysis using flow cytometry had confirmed diploidy in hydropic abortions and complete moles and triploidy in partial moles.Results: Ki-67 immunoreactivity was assessed in villous cytotrophoblasts, syncytiotrophoblasts and stromal cells. Positive cells were found to be restricted mostly to the villous cytotrophoblasts, while syncytiotrophoblasts showed an absence of immunostaining for Ki-67, and occasional weak nuclear staining was seen in the stromal cells. There was a significant difference in Ki-67 immunoreactivity of cytotrophoblastic cells between hydropic abortions and complete moles (P<0.001), hydropic abortions and partial moles (P=0.002) and also between complete and partial moles (P<0.001). On the other hand, there is significant overlap in the Ki-67 immunoreactivity between complete and partial moles (+staining category) and between partial moles and hydropic abortions (+staining category).Conclusions: Despite the significant differences, Ki-67 immunostaining could not be helpful in distinguishing molar placentas from hydropic abortions as well as partial from complete hydatidiform moles, because there are considerable overlaps between results in different categories.

Statement of the Problem: P63 gene is a member of TP53 and its homologous gene family. Its expression was observed in some odontogenic lesions, more expression in aggressive lesions.Purpose: This study aimed to investigate the possible diagnostic impact of P63 protein on dentigerous cysts and various types of ameloblastoma. Its expression with Ki-67 proliferation marker was also compared.Materials and Method: This cross-sectional retrospective study was enrolled on 25 cases of dentigerous cyst including 21 unicystic ameloblastomas and 17 conventional ameloblastomas. The expression of P63 and Ki-67 was assessed by immunohistochemical (IHC) examinations. Data were analyzed by employing Mann-Whitney and correlation coefficient tests.Results: P63 expression was significantly higher in ameloblastoma than unicystic ameloblastoma and dentigerous cysts. There was no significant difference between unicystic ameloblastoma and dentigerous cyst in P63 expression. A 90% cut-off point was obtained for basal layer which gave 88% sensitivity and 78% specificity to distinguish more invasive lesions from others. There was not any correlation between P63 and Ki-67 immunostaining in the three study groups.Conclusion: More aggressiveness and more invasiveness of odontogenic lesions depicted higher rate and also more intensive expression of P63. Moreover, the expression of P63 protein had not any correlation with Ki-67 protein in dentigerous cysts and ameloblastomas.

BACKGROUND: Despite well-described histopathologic criteria, the distinction of spontaneous abortion from hydatidiform mole and complete hydatidiform mole from partial hydatidiform mole remains a problem because of interobserver and intraobserver variability. The aim of this study was to evaluate the value of two immunohistochemical markers in the differential diagnosis of subgroups of lesions of villous trophoblasts and spontaneous abortions.METHODS: Immunohistochemistry with the P63 and Ki-67 antibody was performed in formalin-fixed paraffinembedded samples of non hydropic abortion (n=14), partial hydatidiform mole (n=12), complete hydatidiform mole (n=12) and choriocarcinoma (n=12). The Ki-67 and P63 labeling index (number of positive nuclei/total number of nuclei) for villous stromal cells, cytotrophoblasts and syncytiotrophoblasts were evaluated separately by counting 100 cells of each population. Statistical analysis was carried out by c2 analysis, and the Mann-Whitney U test. Statistical significance was determined at p<0.05 on the basis of 2-tailed tests.RESULTS: None of nonhydropic spontaneous abortions analyzed exhibited positive cytotrotrophoblastic and syncytiotrophoblastic cells for P63. The syncytiotrophoblastic cells were negative for p63 in all of choriocarcinomas. All of choriocarcinomas analyzed exhibited severe expression of Ki-67 in cytotrotrophoblastic cells. None of abortions and partial moles was diffusely labeled with Ki-67.CONCLUSIONS: Ki-67 labeling index in cytotrophoblastic cells is the best index to differentiate between abortion and subgroups of lesions of villous trophoblasts as well as between different subgroups of lesions of villous trophoblasts. Ki-67 is a better marker than P63 to attain this goal.