The Expressions of Tyrosine Kinase Receptors, EphA2, c-met and c-erbB-2 in the Human Breast

BACKGROUND: Tyrosine kinase receptor (TKR) is an important protein for normal-development, growth and tumorigenesis in human tissues. The purpose of this study was to evaluate the effect of TKR in the progression of breast cancer. METHODS: The expressions of EphA2, c-met and c-erbB-2 were examined, by using immunohistochemical methods and RT-PCR, in samples of breast tissue that included 111 samples of normal epithelium, 34 samples of ductal carcinoma in situ (DCIS), and 109 samples of invasive ductal carcinomas (IDC). The results were compared with the prognostic parameters of breast cancer including the tumor grade, growth pattern, lymph node metastasis and the expressions of ER, PR, p53 and Ki-67. RESULTS: The protein expressions of the three TKRs were higher in DCIS and IDC than in normal epithelium. The protein expression of EphA2 was correlated with a tumor grade, a labeling index of Ki-67, and the protein expression of c-met. Overexpression of c-erbB-2 was correlated with lymph node metastasis. The mRNA levels of the three TKRs were correlated with each other in normal tissue and IDC. The level of c-met mRNA was higher in the low grade tumors. CONCLUSIONS: The three TKRs may play roles in the tumorigenesis of human breast cancer. The overexpressions of EphA2 and c-erbB-2 may be a poor prognostic parameter in breast cancers.

CD24 Expression in Gastric Adenocarcinoma Is Associated with Tumor Invasiveness

BACKGROUND: CD24, also referred to as the heat stable antigen in mice, is a glycosyl phosphatidylinositol- linked glycoprotein expressed by thymocytes, B cells, neutrophils and immature neuronal cells. It has been recently observed in a variety of human malignancy. Here, we demonstrated the expression of CD24 in gastric adenocarcinomas. METHODS: A total of 40 gastric adenocarcinomas and 20 tubular adenomas were immunohistochemically examined for the expression of CD24 and matrix metalloproteinase-2 (MMP-2) proteins. The immunoreactivity of CD24 was semiquantitatively scored (0, 1+, 2+) and compared with clinicopathologic variables and MMP-2 expression in tumor cells. RESULTS: CD24 was rarely expressed in normal gastric tissue and not expressed in tubular adenoma. In contrast, a moderate/strong expression (2+) of CD24 was observed in 25% of gastric adenocarcinomas, and 30% cases showed a weak CD24 staining (1+). Moreover, CD24 expression was significantly correlated with the depth of tumor invasion and MMP-2 expression. CONCLUSION: These results suggest that the aberrant expression of CD24 in gastric adenocarcinomas might be associated with tumor progression and invasiveness.

Effect of Atorvastatin, a HMG-CoA Reductase Inhibitor, in Experimental Colitis in Mice

BACKGROUND: The statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, are approved for cholesterol reduction, and may also be beneficial in the treatment of inflammatory disease. In this study, atorvastatin was tested in experimental colitis, a disease model of inflammatory bowel disease. METHODS: To induce colitis, dextran sodium sulfate (DSS) or trinitrobenzene sulfonic acid (TNBS) were administrated to C57BL/6 or BALB/c mice. Mice were monitored daily for loss of body weight and survival for indicated days. Colon length and histology were examined after sacrifice. RESULTS: The administration of DSS induced marked colonic inflammation and shortening, and resulted in a loss of body weight. DSSinduced colitis was not affected by atorvastatin treatment, but in contrast, the administration of atorvastatin relieved TNBS-induced colitis with a resultant rapid recovery of weight loss and a reduction in colonic length shortening. Histologically, inflammatory cell infiltration in the colonic wall, mucosal ulceration and crypt disruption were also suppressed in atorvastatin treated mice. CONCLUSION: These results suggest that atorvastatin preserves intestinal integrity in colitis, probably via the modulation of Th cell-mediated immune response, in a manner independent of innate immunity.

Expression of pS2/TFF1 Protein in Normal Colonic Mucosa, Adenoma and Adenocarcinoma

BACKGROUND: The trefoil factor 1 protein (pS2/TFF1) is a candidate tumor-suppressor protein, and it is a pleiotropic factor involved in the organization and homeostasis of the gastrointestinal tract and various inflammatory or neoplastic diseases. The purpose of this study was to assess the expression of pS2/TFF1 and its clinicopathologic relationship, including the p53 and Ki-67 labeling index, in colorectal carcinogenesis. METHODS: The expression of pS2/TFF1 protein was evaluated immunohistochemically in 45 samples of normal colonic mucosa, 43 samples of adenoma and 186 samples of colorectal carcinoma. RESULTS: pS2/TFF1 protein was expressed weakly in 37.8% of normal colonic mucosa samples, and it had a weak to strong expression in 48.8% of adenomas and 28% of colorectal adenocarcinomas. pS2/TFF1 expression in carcinoma was slightly increased in the poorly differentiated group compared with the well to moderately differentiated group (p=0.059). Interestingly, mucinous carcinoma (4/4) and signet ring cell carcinoma (2/3) showed significant increase of pS2/TFF1 expression. pS2/TFF1 expression was inversely correlated with the p53 protein expression and the Ki-67 labelling index (p<0.05). There was no significant correlation with the tumor size, metastasis or pathologic staging. CONCLUSIONS: Overexpression of pS2/TFF1 expression in colorectal adenocarcinoma was inversely correlated with the Ki-67 labelling index and the p53 expression in cancer. These results suggest that pS2/TFF1 protein may contribute as tumor suppressor factor in colorectal adenocarcinoma.

Expression of Osteoprotegerin and RANK Ligand in Breast Cancer Bone Metastasis

Bone destruction is primarily mediated by osteoclastic bone resorption, and cancer cells stimulate the formation and activation of osteoclasts next to metastatic foci. Accumulating evidences indicate that receptor activator of NF-kB ligand (RANKL) is the ultimate extracellular mediator that stimulates osteoclast differentiation into mature osteoclasts. In contrast, osteoprotegerin (OPG) inhibits osteoclast development. In order to elucidate a mechanism for cancer-induced osteoclastogenesis, cells from a human breast cancer line, MDA-MB-231, were directly co-cultured with ST2, MC3T3-E1, or with primary mouse calvarial cells. Osteoclast-like cells and tartarate resistant acid phosphatase (TRAP) activities were then quantitated. We examined these cell lines and samples from breast cancer by RT-PCR for the expressions of OPG and RANKL mRNA. Compared to controls, co-culture of MDA-MB-231 cells with stromal or osteoblastic cells induced an increase in number of osteoclasts and TRAP activities. MDA-MB-231 cells alone or breast cancer samples did not express RANKL mRNA. However, co-culture of these cancer cells with stromal or osteoblastic cells induced RANKL mRNA expression and decreased OPG mRNA expression. These experiments demonstrate that direct interactions between breast cancer and stromal or osteoblastic cells induce osteoclastogenesis in vitro through modulating RANKL expression.

Expression of p21, p53 and Ki-67, and Apoptosis in Colorectal Adenocarcinoma

BACKGROUND: The purpose of this study is to assess the roles of p21 protein, p53 protein, and Ki-67 expressions and apoptosis in colorectal tumorigenesis. METHODS: Fifty-seven colorectal cancers and 15 villotubular adenomas were investigated by immunohistochemical staining for p21 protein, p53 protein, Ki-67, and in situ labeling of apoptotic cells. Clinicopathologic values (tumor size, histologic grade, Dukes stage, and lymph node metastasis) were compared with the incidence of expressions of p21 protein and p53 protein, index of Ki-67 expression, and apoptosis. RESULTS: The incidence of p21 protein expression was decreased with lymph node metastasis (p<0.005), and that of p53 expression was increased with lymph node metastasis (p<0.005). There were no statistically significant correlations among the p21 protein or p53 protein expressions, tumor size, histologic grade and stage. The correlation between the Ki-67 labeling index and the clinicopathologic values was not statistically significant. The labeling index of apoptosis was increased with the Astler-Coller stage (p<0.05). Statistical analysis revealed a significant inverse correlation between the p21 protein and p53 protein expressions (p<0.05). CONCLUSIONS: It is suggested that p21 protein, p53 protein and the apoptotic labeling index are useful variables for the prognostic assessment of colorectal adenocarcinoma. Down-regulation of p21 protein expression may be associated with poor prognosis. Also, the expressions of p21 protein and p53 protein may play an important role in the tumorigenesis and progression of the colorectal adenoma-carcinoma sequence.

Partial Trisomy 13 (Patau Syndrome): An Autopsy Report

Trisomy 13 (Patau syndrome) is rare and usually fatal if contracted within the first six months of life. We report a case of a male fetus with the typical features of Patau syndrome. He was terminated in a 27-year-old mother at the gestational age of 32+4 weeks. In chromsomal analysis by GTG banding technique, the karyotype of the fetus was 46,XY,rec(13) dup(13q)inv(13)(p13q21.3)(=partial trisomy 13q); and his mother's karyotype was 46,XX, inv(13)(p13q21.3)(=pericentric inversion). His father had normal karyotype, 46,XY. Ultrasonography showed fluid-nature content, which was occupying the entire intracranium, but preserving the brain stem and cerebellum. Postmortem examination disclosed holoprosencephaly, hydrocephalus, a single nostril, bilateral anophthalmia, ventricular septal defect, and a single umbilical artery.

A Case Of Sclerosing Stromal Tumor Of The Ovary / 대한산부인과학회잡지

Sclerosing stromal tumor, which was first described by Chalvardjian and Scully in 1973, is a very rare benign tumor of the ovary. This tumor differs from the fibroma, thecoma and lipoid cell tumor clinically and pathologically by showing prominent pseudolobular pattern and hypervascularity. We experienced a case of sclerosing stromal tumor of the ovary in 38 year-old woman. We report this case with a brief review of the literature.

Expression of Cyclooxygenase-2 Protein in Gastric Carcinogenesis / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The increased expression of cyclooxygenase (COX)-2 has been implicated in the development and progression of human cancers. We investigated COX-2 expression in normal, gastric adenomas and adenocarcinomas. MATERIALS AND METHODS: COX-2 protein was assayed in gastrectomy and biopsy specimens, from 68 gastric adenocarcinomas, 40 gastric adenomas and 35 normal gastric tissues, by immunohistochemistry, and 32 specimens of normal and adenocarcinomas by western blot analysis. Correlation between COX-2 expression and various clinicopathological factors were studied in the gastric adenocarcinoma. RESULTS: COX-2 protein expression in epithelial cells was increased in 6/40 (15%) of the adenomas and 55/68 (80.9 %) of the adenocarcinomas, while normal mucosa was not expressed. COX-2 expression was increased in differ-entiated gastric carcinomas compared with those in the undifferentiated group (p<0.05). The expression of COX-2 protein was unrelated to tumor size, depth of tumor invasion and the presence of lymphatic or vascular invasions. Western blot analysis showed the enhanced expression of the COX-2 protein (23 out of 32)(71%) in gastric carcinomas compared to that of normal gastric mucosal epithelium. CONCLUSION: The above results indicated that the expression of COX-2 protein occurs in dysplastic epithelium and gastric carcinomas, which suggests COX-2 expression may contribute to tumor formation.

Immunoreactivity of CD99 in Stomach Cancer

CD99 is characteristically expressed in Ewing's sarcoma/primitive neuroectodermal tumor. Recently its immunoreactivity has also been reported in other tumors. However, the significance of CD99 isoforms expressed in these tumors has not been elucidated. In this study, we evaluated the expression of CD99 isoforms and its relationship with histopathologic parameters in gastric adenocarcinomas. Paraffin sections of 46 gastric adenocarcinomas were stained with an anti-CD99 monoclonal antibody, YG32. Twelve (26.1%) cases of 46 gastric adenocarcinomas showed immunoreactivity to YG32. The CD99 expression was also seen both in non-neoplastic foveolar epithelial cells and infiltrating lymphocytes. In addition, Western blot and RT-PCR analyses revealed that the type I is the predominant isoform of CD99 in non-neoplastic and neoplastic gastric tissues. The CD99 expression was usually seen in the intestinal type adenocarcinoma, while rarely in the diffuse type. The CD99 immunoreactivity decreased in MMP-2-overexpressing adenocarcinomas (p=0.028). Our results suggest that the type I is the major isoform of CD99 expressed in non-neoplastic gastric mucosa and gastric adenocarcinomas and its downregulation in gastric adenocarcinoma may be associated with cellular dedifferentiation and/or MMP-2 overexpression.

Expression of Senescence-related Proteins in Rat Fracture Callus / 대한정형외과학회잡지

PURPOSE: To evaluate the expression of senescence-related proteins according to the aging process and to determine the role of senescence-related proteins in the bone tissue and their effects on the process of bone union. MATERIALS AND METHODS: 18 Sprague-Dawley rats (8 weeks old: 7, 32 weeks old: 6, and 70 weeks old: 5) were used in the experiment. A unilateral closed femur fracture was made, and the fracture callus was obtained 2 weeks after the fracture. The ossification process was observed in proliferative chondrocytes, the hypertrophic chondrocytes, and in the mesenchymal layer individually by immunohistochemistry, using p16, p21, c-fos and c-jun antibodies. RESULTS: There was no significant differences in the manifestation of p-16, p-21, c-fos, c-jun gene according to the age. The positive ratio of p-16 was maximal in proliferative chondrocytes (54.93%) and decreased in the mesenchymal layer (46.48%), and in hypertrophic chondrocytes (10.85%), in order. The positive ratio of c-fos was maximal in proliferative chondrocytes (73.32%) and decreased in the mesenchymal layer (51.84%), and in hypertrophic chondrocytes (9.64%), in order. CONCLUSION: We believe that senescent genes in the bone tissue participate in the differentiation of osteochondral cells and in the process of fracture callus ossification.

Expression of p21/WAF1/CIP1, p27/KIP1 and p57/KIP2 Proteins in Gastric Adendegrees Carcinoma / 대한암학회지

PURPOSE: p21/WAF1/CIP1, p27/KIP1 and p57/KIP2 are negative regulators of the cell division cycle. We evaluated the expressions of KIP CDK inhibitors and examined the relationship of clinicopathologic parameters and cell proliferation index in gastric adendegrees Carcinomas. MATERIALS AND METHODS: The study was carried by the TUNEL method for apoptosis, immuno histdegrees Chemical staining for PCNA, p53, p21/WAF1/CIP1, p27/KIP1, and p57/KIP2 proteins and Western blot for KIPs proteins of normal and cancer tissues of stomach. RESULTS: In normal gastric mucosa, p21/WAF1/CIP1 and p27/KIP1 proteins were expressed both mainly to the superficial portion of the glands with intestinal metaplasia and stromal cells. p57/KIP2 protein was also expressed normal crypt glandular epithelial and stromal cells. In gastric adendegrees Carcinoma, p21/WAF1/CIP1 was positive in 25 of 70 (35%) and showed significant decrease in deep tumor invasion (p=0.015) and the presence of angioinvasion (p=0.013). There was signi ficant inverse correlation between p27/KIP1 expression and cell proliferating index. p21/WAF1/ CIP1 expression was related to lower apoptotic index. Western blot analysis of KIP CDK inhibitors showed marked down-regulation of p21/WAF1/CIP1 protein in cancer than normal tissue, but alternative expression in p27/KIP1 and p57/KIP2 proteins. CONCLUSION: The above results indicated that the expression loss of KIP CDK inhibitors was contributed to tumor progression and aggressiveness in gastric adendegrees Carcinoma.

Mutation and expression of the p27KIP1 and p57KIP2 genes in human gastric cancer

Cyclin-dependent kinase inhibitors (CDKI) are negative regulators of cell cycle progression by binding the cyclin-CDK complex and inhibiting the CDK activity. Genetic alteration in the CDKI genes has been implicated for carcinogenesis. To test the genetic alteration in the p27 and p57 genes, KIP family CDKI genes, 30 gastric tumor-normal pairs and 8 gastric cancer cell lines were analyzed for mutations by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP). No mutation was detected in these genes although length polymorphisms in the proline-alanine repeat of the p57 gene were detected. When the p27 and p57 mRNAs were analyzed in gastric cancer cell lines by RT-PCR, the p27 mRNA was expressed considerably high in tumor cells but expression of the p57 mRNA was much low in gastric cancer cell lines compared to that of normal cells. The result suggests that inactivation of gene expression rather than mutations in the p57 gene accounts possibly for the involvement of this gene in tumorigenesis of gastric cancer. However, expression of the p27 gene seems to be essential for cell survival.

Huge Chondroid Syringoma of the Forehead: A case report

Chondroid syringoma also known as cutaneous mixed tumor of salivary gland type, is a relatively uncommon adnexal tumor of sweat gland origin. Most of these tumors are benign, although occasional malignant variants have been documented. Commonly, these tumors occur in the head and neck region but any part of the body may be affected. Their usual size is between 0.5-3.0cm. We treated a 47-years-old man was seen for tumor first noticed about 17 years ago on the forehead. This mass had been increasing in size slowly, An 8 x 8 x 9 cm size mass with surrounding subcutaneous tissue and overlying skin was excised from frontalis muscle fascia. On frozen biopsy, there was no malignant change. The wound was covered by skin graft. Microscopically, the mass is composed of glands or tubules, adipose tissue and hyalinized or chondromyxoid stroma(PAS:- , Alcian blue: +). Several areas show adenoic cystic carcinoma pattern, suspicous for early malignant change. No evidence of local recurrence has surfaced after 6 months of operation.

A Case of Merkel Cell Carcinoma / 대한피부과학회지

Merkel cell carcinoma is an uncommon malignancy originally called "trabecular carcinoma" by Toker in 1972. Although the exact origin of the Merkel cell is unknown, it probably arises from neuroendocrine cell of the basal epidermis. It then grows vertically into the dermis and subcutaneous tissue. The tumor usually affects older persons, with a median age at presentation of 66 years. Although its cause is unknown, its propensity to occur on the head, neck, or extremities suggests that sun exposure may play a role. We report a case of a 58-year-old woman who showed a solitary dusky red-colored tumor on the right upper arm. The tumor had rapidly grown since 2 months ago but there was no evidence of regional lymph node and distant metastases. Microscopically, the tumor cells were uniform with round to oval shaped nucleus and scanty cytoplasm, and showed trabecular, anastomosing cord-like arrangement mainly in the dermis and subcutaneous tissue. Ultrastructually, membrane-bound neurosecretory granules were found in the cytoplasm and characteristic perinuclear filaments were retained in each tumor cell. We performed wide local excision with 3cm margin and prophylactic radiation therapy.

Expression of p21 and p53 Proteins in Gastric Adenocarcinoma

Fifty-four adenocarcinomas of stomach were investigated to assess the expression of p21 and p53 using an immunohistochemical method. The relationship between p21 and p53 expression and the clinicopathologic parameters were analysed. The staining pattern of p21/p53 were: p21+/p53+, p21-/p53+, p21+/p53-, and p21-/p53- in 30, 12, 8, and 4 cases, respectively. Loss of p21 expression was observed in 16 of 54 tumor tissues (29%). p21 expression, however, had an inverse correlation with vascular invasion and depth of tumor invasion. The p21 and p53 protein expression showed intratumoral heterogeneity. In 63% of the adenocarcinoma, a proportional relationship was found between p21 and p53 immunostaining. The present results suggest that p53 independent induction of p21 expression may be involved in the molecular mechanism of these tumors, and expression of p21 protein may be related to a favorable prognosis in gastric adenocarcinomas.

p27Kip1 Expression and Apoptotic Index in Prostatic Adenocarcinoma

p27kip1, a cyclin dependent kinase inhibitor, has been recognized as a negative regulator of cell cycle. To investigate the role of p27kip1 on progression of cancer and apoptotic pathway, we analyzed p27kip1 expression using immunohistochemical stain in 40 cases of prostatic adenocarcinoma and apoptotic index by TUNEL method in 30 cases of prostatic adenocarinoma. Both were correlated with Gleason grade and Gleason score. Loss of p27kip1 expression was more frequent in prostatic adenocarcinomas of higher score (Gleason score 7 to 10) (60.7%) than in those of lower score (Gleason score 4 to 6) (33.3%) (p0.05). These results suggest that loss of p27kip1 expression and increased apoptotic index may be the morphologic markers to predict the behavior of prostatic adenocaricnoma. The role of p27kip1 on apoptotic pathway seems to be meager in this study and needs further study.

The Effects of Transforming Growth Factor beta1 on Apoptosis in Rat Hepatocellular Carcinoma

Based upon the concept that carcinogenesis is associated with apoptosis, specific therapies designed to enhance the susceptibility of cancer cells to undergo apoptosis could be developed. Thus, in this paper, it was designed to investigate whether, using rat animal model with chemical-induced hepatocellular carcinoma, TGF-1 in vivo could induce apoptosis in cancer. The chemical hepatocarcinogenic procedure of Solt-Farber method was used on Sprague-Dawley rats. Experimental groups were divided into group A treated with the standard Solt-Farber regimen of diethylnitrosamine (DEN) and 2-Acetaminofluorene (AAF), group B TGF-, group C TGF-1, and group D adriamycin after hepatocellular carcinoma developed. For detection of apoptotic cells, apoptotic indices were examined by the in situ end DNA labelling method. The expression of proliferating cell nuclear antigen was examined by immunohistochemical staining. Apoptosis of rat hepatocellular carcinoma cells increased significantly to 4.92+/-2.32/HPF in the group C compared with the control group (A) (2.54+/-1.13/HPF; P<0.05). Two distinctly different populations of proliferating hepatocellular carcinoma cells were identified. The cells at G1/S boundary (weak granular staining) increased to 15.75+/-6.19/HPF and 6.45+/-2.93/HPF in the groups C and D, respectively, but decreased to 2.42+/-2.06/HPF in the group B compared with the control group (A) (6.38+/-2.18/HPF; p<0.05). The cells at S phase (strong granular staining) increased to 3.37+/-2.69/HPF in the group B but decreased to 0.32+/-0.47/HPF in the group D (p<0.05). In conclusion, these results indicate that the TGF-1 may be used as an effective anticancer agent.

The Expression of TGF-beta1 and TGF-beta Receptor I in Human Lung Cancer

A majority of human lung cancer cell lines have developed resistance to growth inhibition via the activation of transforming growth facter-beta (TGF-beta). Previous studies have reported that growth inhibition of TGF-beta is linked to the expression of transforming growth factor-beta receptor type I (TGF-betaRI). Immunohistochemical studies of TGF-beta1 and TGF-betaRI have been carried out in 43 cases of lung neoplasm; including 25 cases of squamous cell carcinoma, 13 cases of adenocarcinoma, 2 cases of adenosquamous cell carcinoma, and 1 case each of undifferentiated carcinoma, small cell carcinoma and neuroendocrine carcinoma. Reverse transcriptase polymerase chain reaction (RT-PCR) for TGF-beta1 mRNA was also performed in 40 cases of tumors and 14 control cases of normal parenchyme. Immunohistochemically, TGF-beta1 and TGF-betaRI expression were noted in the cytoplasm of all type of tumor cells. The staining intensity and areas were examined and scored from 0 to 5. As a whole, TGF-beta1 staining scores in the neoplastic lesions were higher than that of the adjacent normal parenchyme, bronchial epithelium or alveolar epithelium. However, TGF-betaRI staining scores were generally lower than that of the adjacent normal components. The TGF-beta1 mRNA showed a higher percentage of expression in tumors than in normal control. Tumor size, lymph node metastasis, histological differentiation and histological type of tumors did not correlated with the staining score of TGF-beta1 and TGF-betaRI. These results indicate that although various types of human lung carcinoma cells produce TGF-beta1, they show a reduction in TGF-betaRI, resulting in an escape from growth inhibition by TGF-beta1.

Epstein-Barr Virus and p53 in Laryngeal and Nasopharyngeal Carcinomas

To investigate the correlation between EBV infection and p53 overexpression in laryngeal carcinomas (LC) and nasopharyngeal carcinomas (NPC) in Korea, we analyzed 37 laryngeal squamous cell carcinomas and 33 nasopharyngeal (11 squamous cell and 22 undifferentiated) carcinomas. We used the immunohistochemistry and polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) for p53 overexpression and p53 gene mutation, respectively, and EBER-1 in situ hybridization and PCR using primer for EBNA-1 and EBNA-2 type 1 and 2 for prevalence and the subtype of EBV. The results were as follows; 1) The p53 expression was found in 43.2% of squamous cell LCs, in 54.6% of squamous cell NPCs and in 22.7% of undifferentiated NPCs. The p53 gene mutation was detected in 6 of 23 squamous cell LCs and 3 of 14 undifferentiated NPCs. 2) EBV was detected more frequently in undifferentiated NPCs (95.5%) than in squamous cell NPCs (63.6%) and squamous cell LCs (37.0%). Only type 1 was found in squamous cell LCs and NPCs, whereas both type 1 and type 2 were detected in undifferentiated NPCs. 3) There was no difference according to EBV infection (EBV+ ; 7 cases, EBV- ; 7 cases) in the cases with p53 protein overexpression but mutaion. From the above results, it can be concluded that squamous cell LCs and NPCs are associated with both p53 and EBV, whereas undifferentiated NPCs are more closely associated with EBV than p53. In Korea, both type 1 and 2 are detected in undifferentiated NPCs. Also, our result suggests that EBV infection does not seem to contribute to p53 overexpression. The interrelationship between EBV infection and p53 remains to be further defined.