Objective: To investigate the p53 overexpression and its correlation with neoplastic cell mitosis and apoptosis in 43 nasopharyngeal carcinomas (NPCs). Methods: Forty-three pretreated NPC biopsy samples were randomly collected in the year 1997 for this study. p53 overexpression was detected by LSAB immunohistochemistry using DO-7 primary antibody. Mitotic figures were counted on H&E stained slides, and apoptotic cells on TUNEL-stained slides by use of in-situ cell death detection kit. Both of mitotic and apoptotic cells were quantitated by cell numbers per one high power field (5(40) averagely in terms of mitotic index (MI) and TUNEL index (TI), respectively. To compare the mean MIs of two groups categorized by different percentages of positive p53 positive cells found in NPC specimens was taken for the purpose of designating the criterion of p53 overexpression. And then, the correlation of p53 overexpression with MI and TI was made by statistical analysis. Results: Because statistically significant difference appeared at the criterion of 20%, the p53 overexpression of NPC was defined as≥20% of positive cells found. The p53 overexpression thus could be detected in 37 out of 43 NPCs, reaching 86.05% (37/43). The mean MI (1.87(1.78/HPF) of 37 NPCs with p53 overexpression was significantly higher than that (0.76(0.63/HPF) of 6 NPCs without p53 overexpression, the P value being <0.05. However, there was no statistical difference between the mean TI (24.50(26.66/ HPF) of 37 NPCs with p53 overexpression and TI (23.17(25.30/HPF) of 6 NPCs without p53 overexpression. Conclusions: p53 overexpression of NPC could be designated by ≥20% of positive neoplastic cells found in pretreated NPC specimens, and the rate of which reached 86.05% (37/43). The overexpressed p53 could enhance cell proliferative activity in pretreated NPCs represented by increasing of MI, but showed no effect on neoplastic cell apoptosis.
Objective:To compare the expression of Epstein-Barr virus encoded LMP1 and E-cadherin/b-catenin in primary and metastatic nasopharyngeal carcinoma (NPC) for thepurpose of understanding their relationship. Methods:Twenty-two pairs of biopsies taken from the nasopharynx and cervical lymph node(s) of the same patient withnasopharyngeal carcinoma were collected. The expression of LMP1, E-cadherin and b-catenin was observed onimmunostained slides using LSAB method. Results:The expression rate of LMP1 in the 22 metastatic tumors(86.36%, 19/22) was significantly higher than that in the 22 primary growths (68.18%, 15/22), P<0.05. The meanexpression percentages of E-cadherin and b-catenin inmetastatic tumors (50.11%22.53% and 66.3621.05%respectively) were significantly lower than those in primary growths (71.5224.34 % and 79.40%15.05%, respectivelyP<0.05. There was a positive correlation between theexpressions of E-cadherin and b-catenin either in primary growths or metastatic tumors. Conclusion: The LMP1 imore likely to be expressed in metastatic neoplastic cells of NPC than in primary carcinoma cells, and on the contrary the expression of E-cadherin/b-catenin in metastatic cells was decreased. Accordingly, the LMP1 might have theability to downregulate the expression of E-cadherin/bcatenin, resulting in enhancement of the invasive capacity of metastatic NPC cells.
A proposal concerning the histological typing of primary nasopharyngeal carcinoma is offered in order to coincide with pathologic terms used both by Chinese and foreign pathologists and reflect the achievements in the research field of NPC. This proposal was worked out mainly basing upon the authors’ diagnostic experience gained in the past 30 years and the international criteria for tumor classification. Primary nasopharyngeal carcinoma could be classified into four major types, namely, keratinizing squamous cell carcinoma (KSCC), non- keratinizing carcinoma (NKC), adenocarcinoma (AC) and carcinoma in-situ (CIS). KSCC could be graded as being well, moderately and poorly differentiated according to the amount of keratinization and intercellular bridges presented in the biopsy slide. The NKC is the most frequent type seen in the high-incidence area of NPC, and could also be subdivided into differentiated and undifferentiated variants. Actually, three grades of KSCC and two variants of NKC are a reflection of different degrees of squamous differentiation. They are consistently associated with Epstein-Barr virus (EBV) infection. There are two major categories of nasopharyngeal AC, namely, traditional and salivary-gland type. As contrasted with KSCC and NKC, nasopharyngeal AC is rarely infected with EBV. There are two subtypes of CIS, namely, squamous- and columnar-cell type. The histological typing concerning the primary nasopharyngeal carcinoma offered above is really a practical proposal and also coincided with the international usage. This proposal can be mastered easily and the authors recommend its routine use in diagnostic pathology.
Objective: To observe the morphological features of neoplastic cell apoptosis developed in nude mice transplants with nasopharyngeal carcinoma (NPC) cell lines, CNE-1 and CNE-2, and to investigate the roles of p53, bcl-2 and bax playing in the process of apoptosis. Methods: CNE-1 and CNE-2 cell lines were inoculated and passed in nude mice for 3 generations. The cell apoptosis was detected on H & E and TUNEL staining slides. The expression of p53, bcl-2 and bax were detected by using immunohistochemistry. p53 gene alteration was assayed in cell lines and transplants by PCR-SSCP. Results: A considerable number of neoplastic cells underwent apoptosis in CNE-1 and CNE-2 transplant tissues. The "shrinkage necrosis" and apoptotic bodies were the main appearances of apoptosis. The p53 alteration was detected in exon 8 by PCR-SSCP and p53 protein accumulation observed in the cell smears and nude mice transplant tissue sections. All the transplant tissue sections of 3 passages showed bcl-2 negativity and bax overexpression. Conclusion: The neoplastic cells of CNE-1 and CNE-2 transplants underwent death mainly taking the way of apoptosis. The "shrinkage necrosis" and apoptotic bodies were the main morphological features of apoptosis seen in those transplants. The apoptosis in CNE-1 or CNE-2 nude mice transplant is highly probable through a p53-independent and bax-mediated pathway.
Objective: To investigate p53 overexpression and its correlation with neoplastic cell proliferation and apoptosis in 20 thymic carcinomas. Methods: 20 surgical samples of thymic carcinoma were collected randomly during the past 15 years in the Guangzhou area. Immunohistochemical staining was performed using LSAB method with anti-p53 monoclonal antibody (DO-7) and proliferating cell nuclear antigen (clone PC 10) as primary antibodies. The p53 index was indicated by the number of p53 positive cells among 100 carcinoma cells. More than 25 percentage of p53 positive cells found in tissue sections was recognized as p53 overexpression. Carcinoma cell proliferation activity was assayed by PCNA index (PI), and apoptosis degree was evaluated by TUNEL (TdT-mediated dUTP-X nick end labeling) index (TI) using Boehringer Mannheim In Situ Death Detection Kit. Results: P53 positive cells could be found in vast majority of thymic carcinomas (19120) and the overexpression rate reached 35% (7120). The median PI (40%) of 7 cases with p53 overexpression was higher than that (31 %) of 13 cases without p53 overexpression, but there was no statistical significance that existed between these two data (P>0.05). The median TI (0.5/HPF) of 7 p53 overexpression cases was much lower than that (4.5/HPF) of 13 non-overexpression cases, and there was a significant difference statistically (P<0.05). Conclusion: p53 expression was a frequent finding in thymic carcinoma cells, and the p53 overexpression which might represent p53 inactivation or gene mutation was often involved in thymic carcinogenesis. The median PCNA index of p53 overexpression group was higher than that of non-overexpression group though there existed no statistical difference. This indicates that the inhibiting function of p53 on cell proliferation seemed lost in p53 overexpressed thymic carcinomas. It is worthy to be specially mentioned that the inducing function of p53 on cell apoptosis was markedly lost in p53 overexpressed thymic carcinomas. Taken together, the overexpresse
