Expression of pRb and E2F-1 and telomerase activity in ameloblastoma / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the expression of pRb and E2F-1, and the association between their expression and the activity of telomerase (hTERT) or cyclin E in human ameloblastoma (AB), and to explore the clinical biological characteristics of AB.</p><p><b>METHODS</b>The expressions of pRb, E2F-1, cyclin E and hTERT mRNA in human AB were detected by in situ hybridization or immunohistochemistry (SP method).</p><p><b>RESULTS</b>The positive expression ratio of pRb in the cell nucleus of AB was 20.4% (11/54). The positive ratio of E2F-1, cyclin E and hTERT mRNA was 92.6% (50/54), 66.7% (36/54) and 94.4% (51/54), respectively. With AB recurrence and malignant transformation, the expression of hTERT, E2F-1, cyclin E was up-regulated. hTERT and cyclin E or E2F-1 mRNA had high positive relation (Spearsman'r(s) = 1.000, P = 0.0001).</p><p><b>CONCLUSIONS</b>The regulatory pathway of Rb/E2F-1 is associated with the cell proliferation and in differentiation of AB. The activity or release of telomerase may be related to the lower expression of Rb and higher expression of E2F-1, and is up-regulated in G(1) late phase by cyclin E.</p>

The study of the invasive biologic behavior of ameloblastoma / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the invasive biologic behavior of ameloblastoma (AB) and to analyze its correlative factors.</p><p><b>METHODS</b>The specimens of 43 cases of AB (primary AB 16 cases, recurrent AB 21 cases, malignant AB 6 cases) were examined immunohistochemically using the streptavidin-biotin method to determine the expression of E-cadherin (E-cad), matrix metalloproteinase (MMP)-2, MMP-9 and vascular endothelial growth factor (VEGF).</p><p><b>RESULTS</b>The cells in malignant AB scattered more, grew invasively, and the basal membrane ruptured or lost. The expression of E-cad in AB descended, MMP-2 and MMP-9 were strongly expressed in the epithelia cells of 28/41, 30/43 cases of AB, respectively. The positive rate and intensity of VEGF increased as AB recurred and transformed malignantly. The expression of E-cad, MMP-9 and VEGF were related to recurrence or malignant transformation of AB (r(s) = 0.309, 0.519, 0.381, P < 0.05).</p><p><b>CONCLUSION</b>AB is a high invasive tumor. The biological behavior of AB is related to lost or abnormal expression of E-cad, the high expression of MMP-2, MMP-9, and VEGF.</p>

Expression of telomerase activity and cyclin A in ameloblastoma / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study relation of the expression of hTERT mRNA and cyclin A, p53 protein, proliferation cell nuclear antigen (PCNA) in ameloblastoma (AB) and to investigate clinical biological characteristics of AB.</p><p><b>METHODS</b>The hTERT mRNA was detected by in situ hybridization, cyclin A, p53 protein and PCNA by SP method. Normal oral mucosa and odontogenic keratocyst (OKC) are comparition.</p><p><b>RESULTS</b>The positive ratio of hTERT mRNA was 1/7 cases in normal oral mucosa. The expression of cyclin A, p53 and PCNA in normal oral mucosa were similar, and the positive cells distributed in stratum basale. In OKC, the positive cells distributed in stratum basale and super-strrtum basale. And the positive ratio of hTERT, cyclin A, p53, PCNA in OKC was 14/16 cases, 4/32 cases, 11/25 cases, 5/9 cases, respectively. In AB, the positive ratio of hTERT mRNA, cyclin A, p53 protein and PCNA was 94.4% (51/54), 66.7% (40/60), 85.7% (42/49) and 78.1% (25/32), respectively. A strong correlation was found between hTERT mRNA with cyclin A, p53 protein and PCNA (r(s) = 0.914, 0.848, 0.804, P < 0.05).</p><p><b>CONCLUSIONS</b>The expression of hTETR mRNA, cyclin A, p53 and PCNA is different in different tissues and lesions, and correlates with cell differentiation and clinical biology behaviour. Telomerase activity is related to cumulation of p53 protein, related to cell proliferation and differentiation, regulated by cyclin A, and higher in S phase.</p>