Adriana Souza de Jesus

MCM3 could be a better marker than Ki‐67 for evaluation of dysplastic oral lesions: an immunohistochemical study

BACKGROUND The aim of this study was to identify the expression of MCM3, Ki-67 and p27 in normal mucosa, leucoplakia and oral squamous cell carcinoma (OSCC) and determine whether altered expression could serve as a prognostic marker of a malignant progression of dysplastic lesions. METHODS The samples were collected from 37 patients with oral leucoplakia (13 with mild dysplasia - MLD, 12 with moderate dysplasia - MD and 12 with severe dysplasia - SD). Eleven samples of mouth floor mucocele (M) and 50 floor mouth and tongue samples OSCC of untreated patients were included in this study. Immunohistochemical expression of MCM3, Ki-67 and p27 of all the groups was analysed. Kruskal-Wallis and Dunns test were used to determine differences among groups, and a Pearsons correlation test was used to evaluate the correlation between the proteins. RESULTS Ki-67 expression was higher in OSCC than M (P < 0.001) and MLD (P < 0.01) groups, and there was a lower expression in M compared with MD and SD (P < 0.05). Regarding p27, its expression was lower in OSCC compared with M, MD and SD. MCM3 expression was lower in M compared with SD and OSCC (P < 0.001), and MLD showed a lower expression when compared SD (P < 0.01) and OSCC (P < 0.001). Moreover, a better correlation was observed between the proteins MCM3 and p27 than between Ki-67 and p27 proteins when all lesions were examined together. CONCLUSIONS This study showed that MCM3 could be a better marker than Ki-67 for evaluation of dysplastic oral lesions.

Tissue microarray use for immunohistochemical study of ameloblastoma

BACKGROUND Ameloblastoma is a locally aggressive odontogenic tumor with high rates of recurrence. To better understand the molecular basis of ameloblastoma, tissue microarray (TMA) may represent a useful tool. However, despite TMA has been considered a high-throughput technique for different human neoplasms, it remains to be validated in the ameloblastoma context. Therefore, the objective of this study was to validate TMA for immunohistochemical study of ameloblastoma, determining its most appropriate design. METHODS Forty cases of ameloblastoma were manually distributed in two TMA blocks assembled in triplicate containing 1.0- and 2.0-mm cores (20 cases each). Immunohistochemistry for cytokeratins 14 and 19, and Bcl-2 and Ki-67 was performed, and semiquantitative analysis was performed. Results obtained with TMA sections were compared to their corresponding conventional whole-section slides (CWSS). RESULTS Kappa statistical test demonstrated that both 1.0- and 2.0-mm cores assessed as duplicate or triplicate significantly correlated with CWSS, with higher levels obtained using Ki67 (k = 0.98, 0.97, 0.88, 0.87) and CK19 (k = 0.62, 0.58, 0.85, 0.85). There was no significant difference between 1.0- and 2.0-mm cores, and between duplicate and triplicate values. 1.0-mm TMA showed a higher index of core loss (33.74% vs. 4.99%). CONCLUSION Using a manual arrayer, it was demonstrated that 1.0-mm TMA arranged in duplicate is a valid method for ameloblastoma immunohistochemical study with satisfactory levels of agreement between TMA cylinders and CWSS.

p-Akt and its relationship with clinicopathological features and survival in oral squamous cell carcinoma: an immunohistochemical study.

BACKGROUND The aim of this study was to evaluate, through immunohistochemical reaction in samples of oral squamous cell carcinoma, the correlation between the expression status of protein kinase B (p-Akt) and patient survival as well as histological grade and some clinicopathological features. METHODS Samples were collected from 46 patients with oral squamous cell carcinoma. The immunohistochemical expression of p-Akt was analysed, as were clinicopathological features including the use of tobacco, tumour stage, size and infiltration of metastatic lymph nodes. The association of immunostaining with histological grade was analysed in 40 patients. The associations were examined for statistical significance using a chi-square test. Overall survival rates were estimated by the Kaplan-Meier method and compared using a log rank test (P > 0.05). RESULTS The results indicated a statistically significant association with p-Akt immunostaining for the variables lymph node metastasis (P = 0.006), tumour size (P = 0.044) and survival rate (P = 0.0298). CONCLUSION From these results, the present study suggests that high p-Akt expression found in oral squamous cell carcinoma patients may contribute to tumour growth, metastasis to regional lymph nodes and shorter survival time.

Effect of 17-allylamino-17-demethoxygeldanamycin (17-AAG) on Akt protein expression is more effective in head and neck cancer cell lineages that retain PTEN protein expression

OBJECTIVES The aim of this study was to evaluate the expression of Akt, PTEN, Mdm2 and p53 proteins in three different head and neck squamous cell carcinoma (HNSCC) cell lines (HN6, HN19 and HN30), all of them treated with epidermal growth factor (EGF) and 17-allylamino-17-demethoxygeldanamycin (17-AAG), an inhibitor of Hsp90 protein. MATERIAL AND METHODS Immunofluorescence and western blot were performed in order to analyze the location and quantification, respectively, of proteins under the action 17-AAG and EGF. RESULTS Treatment with EGF resulted in increased levels of Akt, PTEN and p53 in all cell lineages. The expression of Mdm2 was constant in HN30 and HN6 lineages, while in HN19 showed slightly decreased expression. Under the action 17-AAG, in HN6 and HN19, the expression of PTEN and p53 proteins was suppressed, while Akt and Mdm2 expression was reduced. Finally, in the HN30 cell lineage were absolute absence of expression of Akt, Mdm2 and p53 and decreased expression of PTEN. CONCLUSION These data allow us to speculate on the particular utility of 17-AAG for HNSCC treatment through the inhibition of Akt protein expression, especially in the cases that retain the expression of PTEN protein.