Comprehensive Bioinformatic Investigation of TP53 Dysregulation in Diverse Cancer Landscapes.

P53 overexpression plays a critical role in cancer pathogenesis by disrupting the intricate regulation of cellular proliferation. Despite its firmly established function as a tumor suppressor, elevated p53 levels can paradoxically contribute to tumorigenesis, influenced by factors such as exposure to carcinogens, genetic mutations, and viral infections. This phenomenon is observed across a spectrum of cancer types, including bladder (BLCA), ovarian (OV), cervical (CESC), cholangiocarcinoma (CHOL), colon adenocarcinoma (COAD), diffuse large B-cell lymphoma (DLBC), esophageal carcinoma (ESCA), head and neck squamous cell carcinoma (HNSC), kidney chromophobe (KICH), kidney renal clear cell carcinoma (KIRC), liver hepatocellular carcinoma (LIHC), lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC), and uterine corpus endometrial carcinoma (UCEC). This broad spectrum of cancers is often associated with increased aggressiveness and recurrence risk. Effective therapeutic strategies targeting tumors with p53 overexpression require a comprehensive approach, integrating targeted interventions aimed at the p53 gene with conventional modalities such as chemotherapy, radiation therapy, and targeted drugs. In this extensive study, we present a detailed analysis shedding light on the multifaceted role of TP53 across various cancers, with a specific emphasis on its impact on disease-free survival (DFS). Leveraging data from the TCGA database and the GTEx dataset, along with GEPIA, UALCAN, and STRING, we identify TP53 overexpression as a significant prognostic indicator, notably pronounced in prostate adenocarcinoma (PRAD). Supported by compelling statistical significance (p < 0.05), our analysis reveals the distinct influence of TP53 overexpression on DFS outcomes in PRAD. Additionally, graphical representations of overall survival (OS) underscore the notable disparity in OS duration between tumors exhibiting elevated TP53 expression (depicted by the red line) and those with lower TP53 levels (indicated by the blue line). The hazard ratio (HR) further emphasizes the profound impact of TP53 on overall survival. Moreover, our investigation delves into the intricate TP53 protein network, unveiling genes exhibiting robust positive correlations with TP53 expression across 13 out of 27 cancers. Remarkably, negative correlations emerge with pivotal tumor suppressor genes. This network analysis elucidates critical proteins, including SIRT1, CBP, p300, ATM, DAXX, HSP 90-alpha, Mdm2, RPA70, 14-3-3 protein sigma, p53, and ASPP2, pivotal in regulating cell cycle dynamics, DNA damage response, and transcriptional regulation. Our study underscores the paramount importance of deciphering TP53 dynamics in cancer, providing invaluable insights into tumor behavior, disease-free survival, and potential therapeutic avenues.

Sinonasal Adenocarcinoma: Clinicopathological Characterization and Prognostic Factors.

Sinonasal (SN) malignancies are rare. Within SN adenocarcinomas, the most frequent are intestinal-type adenocarcinomas (ITACs). ITAC has been associated with wood and leather dust occupational exposure and TP53 mutations. Not much information is available regarding its characterization and treatment. The aim of this study is to characterize the clinicopathologic and prognostic factors of patients with sinonasal adenocarcinomas (SNACs) treated in our tertiary-level hospital. A retrospective, consecutive study including SNAC patients diagnosed between 2004-2023 was conducted. Clinicopathological data was collected, and p53 status was assessed in the tumor specimens. The association between p53 status and clinicopathological variables, as well as their impact on survival, was evaluated. In total, 35 were included, most of them having ITAC (91.4%) with papillary subtype (37.5%); the majority were subjected to occupational risk exposure (82.9%). Overexpression of p53 was identified in 48.6% of the tumors. Papillary and colonic subtypes were associated with higher median progression-free survival (mPFS) than mucinous and solid subtypes (mPFS 37 months, 95% CI, 20.0-54.0, vs. 9 months, 95% CI, 7.15-10.85, p=0.01); the former was also associated with higher median overall survival (mOS) (mOS 64 months, 95% CI, 37.18-90.81 vs. 14 months, 95% CI, 0-41.58, p=0.02). Histologic grade 1-2 and macroscopic complete resection were associated with higher PFS (PFS of five months of 90.9% vs. 33.3%, p=0.01; mPFS of 37 months, 95% CI, 4.93-69.07 vs. 10 months, 95% CI, 6.43-13.57, p=0.04, respectively). Disease recurrence with distant metastases was associated with lower OS (11 months, 95% CI, 6.1-15.9 vs. 53 months, 95% CI, 22.70-83.30, p=0.04). This study reinforces the importance of protective occupational measures. Future studies will be important to validate the best treatment strategy in the advanced stages of this disease and also to identify new prognostic and/or therapeutic target biomarkers in SNAC.

P53 Overexpression May Represent an Early Marker of Clinicopathologic Progression in Vasculogenic Mesenchymal Lesions of Germ Cell Tumor Origin.

Vasculogenic mesenchymal lesions (VMLs) of germ cell tumor origin are thought to originate in postpubertal-type yolk sac tumor components and include a spectrum of lesions from teratoma with vasculogenic stroma (TVS), to low and high-grade vasculogenic mesenchymal tumors (VMTs). VMLs exhibit rudimentary to well-developed neoplastic vessels within primitive mesenchyme, being considered a neoplastic reiteration of embryonic vasculogenesis in the splanchnic mesoderm of the yolk sac. They occur in patients with primary mediastinal germ cell tumors after chemotherapy, and a subset progresses to "somatic-type" sarcomas [including angiosarcoma (AS)], with high-grade VMTs likely portending a higher risk. Recently, we encountered a low-grade VMT that progressed to metastatic AS during follow-up. In this case, both the low-grade VMT and the subsequent AS demonstrated p53 overexpression, suggesting that p53 alterations may precede histopathologic transformation. To test this hypothesis, we evaluated neoplasms representing the entire spectrum of VMLs using p53 immunohistochemistry (IHC; clone DO-7, Dako). Overexpression was defined as nuclear positivity in > 80% of neoplastic cells. Because the distinction between high-grade VMT and AS can be subjective in some cases, they were grouped together in a single category. Thirty-nine VMLs were assessed: 16 high-grade VMT/AS, 19 low-grade VMT, and 4 TVS. Patient age ranged from 19 to 46 years (mean, 30 years; male = 97%). Four high-grade VMT/AS and one low-grade VMT showed p53 overexpression (5/39 VMLs, 13%; 4/16 high-grade VMT/AS, 25%). These tumors included 1 unequivocal AS and 1 high-grade VMT/AS with progression to rhabdomyosarcoma. The only low-grade VMT with p53 overexpression demonstrated progression to AS. Another high-grade VMT that progressed to sarcoma demonstrated p53 overexpression in the sarcoma component, but it was excluded because the VMT was not represented in the material available at the time of the study. Lesions with intratumoral grade heterogeneity (classified based the highest grade), demonstrated more pronounced p53 overexpression in the high-grade components. P53 overexpression is associated with disease progression in a subset of VMTs and may precede morphologic transformation to sarcoma. Routine evaluation of VMTs with p53 IHC seems justified, with overexpressors likely requiring an close clinical surveillance.

Different effects of p53 protein overexpression on the survival of gastric cancer patients according to Lauren histologic classification: a retrospective study.

BACKGROUND: Inactivation of TP53, a tumor suppressor gene, is associated with the development of several malignancies, including gastric cancer (GC). The present study aimed to evaluate the correlation between the overexpression of p53 and survival in different Lauren-type GCs. METHODS: From May 2003 to December 2019, 3608 GC patients treated endoscopically or surgically at the Seoul National University Bundang Hospital were enrolled for the study. Immunohistochemical staining for p53 was performed on all endoscopic and surgical gastric specimens. Clinicopathologic characteristics with Lauren classification, survival rate, and cancer recurrence were analyzed according to p53 overexpression. RESULTS: Among 3608 GC patients, p53 overexpression was seen in 1334 patients (37%). p53 overexpression was associated with lower depth of invasion (P = 0.026) and Early gastric cancer (P = 0.044) in intestinal-type GC, and with advanced TNM stage (P < 0.001) and Advanced gastric cancer (P < 0.001) in diffuse-type GC. The overall survival (OS) and GC-specific survival (GCSS) were significantly lower in p53 overexpression positive patients. This significance was more pronounced and enhanced in the diffuse-type GC and was absent in the intestinal-type GC. In multivariate analyses, p53 overexpression was associated with poor OS in both subtypes of GC and cancer recurrence in diffuse-type GC. (OS in intestinal-type: adjusted hazard ratio [aHR] = 1.423, P = 0.022; OS in diffuse-type: aHR = 1.401 P = 0.035; cancer recurrence in diffuse-type: aHR = 1.502, P = 0.039). CONCLUSION: p53 overexpression was associated with poor prognosis in GC, especially in diffuse-type. In addition, p53 overexpression was associated with early stage disease in intestinal-type GC and with advanced stage disease in diffuse-type GC.

Optimized Icariin Cubosomes Exhibit Augmented Cytotoxicity against SKOV-3 Ovarian Cancer Cells.

Clinical application of icariin (ICA) is limited, despite its activity against cancer growth, because of the low solubility of ICA in an aqueous environment. Therefore, the present study attempted to develop and optimize ICA-loaded cubosome delivery and to explore its efficacy and possible mechanism of action against ovarian cancer. The optimization of the cubosome formulation was performed using the Box‒Behnken statistical design; during the characterization, the particle sizes were in the range of 73 to 183 nm and the entrapment efficiency was 78.3% to 97.3%. Optimized ICA-loaded cubosomes (ICA-Cubs) exhibited enhanced cytotoxicity and apoptotic potential, compared with ICA-raw, against ovarian cancer cell lines (SKOV-3 and Caov 3). The optimized ICA-Cubs showed a relatively non-cytotoxic effect on normal EA.hy926 endothelial cells. Further analysis of cell cycle arrest suggested a potential role in the pre-G1 and G2/M phases for ICA-Cubs in comparison with ICA-raw. ICA-Cubs increased the generation of reactive oxygen species (ROS) and the overexpression of p53 and caspase-3 in the SKOV-3 cell line. In conclusion, the cubosomal delivery of ICA might provide a prospective approach towards the superior control of ovarian cancer cell growth. Its improved efficacy compared with that of the free drug might be due to the improved solubility and cellular permeability of ICA.

The Association and Significance of p53 in Gynecologic Cancers: The Potential of Targeted Therapy.

Dysfunction of p53 is observed in the many malignant tumors. In cervical cancer, p53 is inactivated by degradation through the complex with human papilloma virus (HPV) oncoprotein E6 and E6-associated protein (E6AP), an E3 ubiquitin protein ligase. In endometrial cancer, overexpression of p53 in immunohistochemistry is a significant prognostic factor. A discrepancy between p53 overexpression and TP53 mutations is observed in endometrioid endometrial cancer, indicating that the accumulation of p53 protein can be explained by not only gene mutations but also dysregulation of the factors such as ERß and MDM2. Furthermore, the double-positive expression of immunoreactive estrogen receptor (ER) ß and p53 proteins is closely associated with the incidence of metastasis and/or recurrence. High-grade serous ovarian carcinoma (HGSC) arises from secretary cells in the fallopian tube. The secretary cell outgrowth (SCOUT) with TP53 mutations progresses to HGSC via the p53 signature, serous intraepithelial lesion (STIL), and serous intraepithelial carcinoma (STIC), indicating that TP53 mutation is associated with carcinogenesis of HGSC. Clinical application targeting p53 has been approved for some malignant tumors. Gene therapy by the adenovirus-mediated p53 gene transfer system is performed for head and neck cancer. A clinical phase III trial using MDM2/X inhibitors, idasanutlin (RG7388) combined with cytarabine, is being performed involving relapse/refractory acute myeloid leukemia patients. The use of adenoviruses as live vectors which encode wild-type p53 has given promising results in cervical cancer patients.

Targeted Genomic Sequencing Reveals Novel TP53 In-frame Deletion Mutations Leading to p53 Overexpression in High-grade Serous Tubo-ovarian Carcinoma.

BACKGROUND/AIM: High-grade serous carcinoma (HGSC) is the most common histological subtype of ovarian carcinoma. Somatic mutation of tumor protein 53 (TP53) is a hallmark of tubo-ovarian HGSC and is observed in almost all such cases. Highly sensitive targeted genomic sequencing can be used to identify novel mutations that may become potential druggable targets and aid in therapeutic decisions. The aim of this study was to describe the clinicopathological and molecular characteristics of HGSCs with novel somatic TP53 mutations identified by next-generation sequencing (NGS). MATERIALS AND METHODS: A commercial NGS panel comprising 170 genes, including TP53, was used to analyze the genetic profiles of 132 ovarian carcinoma cases. The clinicopathological characteristics and p53 immunostaining results of two HGSCs exhibiting novel TP53 mutations were investigated. RESULTS: Eighty-eight (66.7%) out of 132 ovarian carcinoma cases were diagnosed as HGSC. Novel TP53 in-frame deletion mutations c.719_727delGTTCCTGCA (p53 p.Ser240_Cys242del) and c.634_642delTTTCGACAT (p53 p.F212_H214del) were detected in a single case of HGSC each. Both patients were postmenopausal women. Imaging and laboratory studies revealed peritoneal carcinomatosis and elevated levels of serum tumor markers. The patients underwent primary debulking surgery and were diagnosed as having stage IIIC HGSC. In both cases, p53 immunostaining revealed uniform nuclear immunoreactivity in 90% or more of tumor cells at a very strong intensity. CONCLUSION: Targeted genomic sequencing revealed novel in-frame deletion mutations of TP53 leading to p53 overexpression in tubo-ovarian HGSC. This discovery of previously unreported somatic TP53 mutations provides insight into the translation of NGS technology into personalized medicine and identifies new potential targets for therapeutic applications.

Different TP53 mutants in p53 overexpressed epithelial ovarian carcinoma can be associated both with altered and unaltered glycolytic and apoptotic profiles.

BACKGROUND: p53 is a tumor suppressor and key regulator of glycolysis in cancer cells, however highly mutated in tumors. In ovarian cancer, studies concerning p53 mutations focus on the DNA binding domain since the majority of hotspot mutations affects this region. Yet, mutations in other regions such as the proline rich domain may also affect the protein's expression and activity. The aim of this study is to investigate the effect of various positions of mutations in TP53 gene on glycolysis, apoptosis and transcription of p53 target genes. METHODS: Mutations frequency and their effect on p53 expression were assessed by PCR-SSCP, sequencing and immunohistochemistry on 30 ovarian cancer biopsies. Six tumors were cultured, as well as SK-OV-3, OVCAR-3 and Igrov-1. SK-OV-3 cells were transfected with 2 TP53 mutants. p53 transcriptional activity was assayed by qPCR, apoptosis by flow cytometry and glycolysis by glucose and lactate measurements, with quantification of glycolytic enzymes expression. RESULTS: Our results showed a high frequency of the P72R mutant, associated with p53 overexpression in the ovarian biopsies. However, P72R mutant cells showed similar apoptosis and glycolysis as WT cells. DNA binding domain mutations decreased the transcriptional activity of the protein and increased glucose consumption and lactate production. CONCLUSION: Despite the overexpression of the P72R mutated protein in the biopsies, it showed a similar apoptotic activity and glucose regulation ability as WT p53. Knowing that p53 expression status is used for chemotherapeutic approaches and prognosis in ovarian cancer, the results obtained highlight the importance of locating TP53 mutations.

Definition of p53 overexpression and its association with the clinicopathological features in luminal/HER2-negative breast cancer.

AIMS: A suitable cut-off value for p53 overexpression and its usefulness as a prognostic factor in luminal/HER2-negative breast cancer were evaluated. PATIENTS AND METHODS: A retrospective analysis of 1,987 patients with luminal/HER2-negative breast cancer who underwent surgery between 2001 and 2009 was performed. RESULTS: p53 expression ≥50% was present in 9% of the patients. Moreover, these patients had significantly lower estrogen/progesterone receptor-positive rates, higher Ki-67 values, larger tumors, disease-positive nodes, higher nuclear grade, and shorter disease-free survival than patients with p53 expression <50% (p<0.0001). Therefore, status of p53-positive cells ≥50% was classified as p53 overexpression. These findings indicate that p53 overexpression is associated with unfavorable characteristics and prognosis. CONCLUSION: The suitable cut-off value for p53 overexpression was determined to be 50%, and p53 overexpression appears to be a significant prognostic factor in patients with luminal/HER2-negative breast cancer.

Two Cases of Acute Leukemic Transformation with a Chromosome 17 Abnormality and p53 Overexpression Evolving from Essential Thrombocythemia

Essential thrombocythemia (ET) is a clonalmyeloproliferative disorder that can rarely transform into acute leukemia in 1~5% of cases. A recent study has found that a significant proportion of leukemic cases from ET were associated with a cytogenetic abnormality (17p deletion). Herein, we report two cases of acute myeloid leukemic transformations harboring a 17p abnormality from a series of 119 ET patients. The first case, a 48-year-old female, developed acute myeloid leukemia with maturation (AML-M2) accompanying myelodysplasia was diagnosed 6.1 years after the initial diagnosis of ET. She was treated with hydroxyurea. Her karyotype showed a monosomy 17. The second case, a 61-year-old male, developed acute megakaryoblastic leukemia (AML-M7) with a very complex hyperdiploidy including addition of 17p13 that developed 6.5 years after the initial diagnosis. He was treated with hydroxyurea and anagrelide. The immunohistochemistry showed p53 overexpression in both cases. Our cases support the specificity of chromosome 17 abnormality and p53 overexpression in acute leukemic transformation from ET.

Frequency of Mutation of Codon 249, Overexpression of p53, and Hepatitis B Virus DNA Positivity in Hepatocellular Carcinoma / 대한임상미생물학회지

BACKGROUND: In hepatocellular carcinoma (HCC), the frequency of p53 mutation and the association with hepatitis B virus (HBV) infection varies with geographic locations and risk factors. The aim of this study was to determine the frequency of codon 249 mutation of p53, p53 overexpression, and HBV DNA positivity and to observe the relationship between them in Korean HCC. METHODS: We analyzed overexpression of p53 in hepatoma tissue from 17 HCC patients by immunohistochemistry (IHC), specific mutations at the third base position of codon 249 by PCR-restriction fragment length polymorphism (PCR-RFLP) method, and presence of HBV by nested PCR. RESULTS: Although a point mutation at codon 250 was seen in one (5.8%) of 17 patients, no codon 249 mutations were found in the patient cohort. The p53 protein was overexpressed in 4 (23.5%) of 17 HCCs. PCR for HBV DNA from HCCs showed a positivity rate of 82.4% (14 of 17 specimens). CONCLUSION: In HCC of this study, HBV infection was not associated with either 249 mutation or overexpression of p53, and overexpression of p53 protein seemed to be related to other than this mutation.

p53 Gene Mutation, Tumor p53 Protein Overexpression, and Serum Anti-p53 Antibody in Patients with Gastric Cancer

PURPOSE: The clinical implication of p53 mutation in gastric cancer is still unclear, as shown by the discordant results that continue to be reported in the literature. MATENRIALS AND METHODS: To assess p53 gene mutation, tumor p53 overexpression, and serum anti-p53 antibody, we employed a polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis, an immunohistochemistry using monoclonal antibody DO-7, and an enzyme-linked immunosorbent assay (ELISA), respectively. RESULTS: Of 169 surgical specimens of gastric cancer, mutation at exon 5~8 of the p53 was identified in 33 (19.5%) and was significantly correlated with lymph node metastasis. Overexpression of p53 was found in 62 specimens (36.7%) and had a significant correlation with tumor differentiation. Serum anti-p53 antibody was positive in 18 patients (10.7%). Twenty-three of the mutated tumors (69.7%) and 39 of the non-mutated tumors (28.7%) displayed immunoreactivity. Twelve of the immunopositive tumors (19.4%) and 6 of the immunonegative tumors produced anti-p53 antibody. These differences were statistically significant (P<0.001 and P=0.005, respectively). There was no significant difference in survival according to the mutation of p53. CONCLUSION: Mutation and overexpression of p53 can be easily detected by immunohistochemistry. However, standardization of the immunohistochemical staining method, as well as guidelines for interpreting the stained result, will produce concordant results and thereby improve clinical application.

The Prognostic Significance of the p53 Overexpession on Complete Response and Survival in Preoperative Chemoradiotherapy Treated Squamous Cell Esophageal Carcinoma / 대한암학회지

PURPOSE: To determine the frequency of p53 overexpression and to analyse the relationship between p53 overexpression and complete response rate, survival in locoregionl squamous cell esophageal cancers treated with preoperative chemoradiation multimodality approaches. MATERIALS AND METHODS: Using a microwave oven heating method, we have detected p53 overexpression by immunohistochemically with a monoclonal antibody(DO-7) in formalin- fixed paraffin-embedded samples of 42 patients with locoregional squamous cell esophageal cancer, who treated with concurrent chemotherapy and radiatian followed by surgery. RESULTS: In 27 of 42 tumors(64.2%), nuclear immunoreactivity for the p53 protein was detected. Complete response rate, evaluated in surgical specimen 3-4 weeks after chemoradiation seemed to be high in p53 positive group compared to p53 negative group, however, there was no statistically significant difference in acquiring better complete response rate, overall survival and progression free survival between p53 positive and p53 negative group(p=0.0546, p=0.0599, p= 0.6832). Complete response group(n=17) survived longer than non-complete response group(n=25)(p=0.0010). CONCLUSION: The results indicate that p53 is not a statistically significant prognostic factor in obtaining better complete response rate, overall survival and progression free survival of the patients with esophageal carcinoma treated with preoperative chemoradiotherapy. Additional studies are warranted for further evaluation.

Overexpression of p53 as a Prognostic Marker in Breast Cancer

BACKGROUND: The treatment plan for breast cancer depends on the axillary lymph-node status. Because of improved screening methods, the number and the proportion of node-negative patients are increasing, leading to a need to search for a reliable prognostic marker. Assessment of prognostic markers, is of major concern for the application of adjuvant treatment regimens, independenent of the axillary lymph-node status. METHODS: The study samples consisting of 96 primary breast cancer tissues were analyzed immunohistochemically for the presence of p53 protein in a paraffin-embedded material. The reaction to monoclonal mouse anti-human p53 protein (DAKO-p53, DO-7) (DAKO, Denmark) produced our experimental data. RESULTS: Nuclear accumulation of the p53 protein suspected to be an independent marker of dedifferentiation, regardless of the lymph-node status. In our study the p53 positivity was 56.25% (54/96), and statistically p53 positivity was not affected by menopausal status, lymph-node metastasis, tumor size, age, presence of the estrogen receptor and the progesterone receptor, and pathologic grading. CONCLUSION: We weren't able to prove statistically that overexpression of p53 is an independent prognostic factor in breast cancer. With more cases of breast cancer involving the monoclonal antibody, a study of the correlation of overall survival and disease-free survival with lymph-node metastasis, pathologic grade, and p53 overexpression is necessary to decide on an early breast-cander treatment modality by using a prognostic marker such as p53.

P53 overexpression in gastric adenocarcinoma with Helicobacter pylori infection

Gastric carcinogenesis has been studied in various aspects. Helicobacter pylori (Hp) infection and mutation of the p53 tumor suppressor gene have recently been argued to be important factors of gastric carcinogenesis. There have been many studies to determine the precise mechanism of how Hp is related to gastric cancer, but it is so far still unknown. We studied the relationship of Hp infection and p53 overexpression and tried to discover some significance in clinicopathologic factors such as age, sex, stage, site, differentiation and gross morphology. Ninety-six patients who were diagnosed with gastric cancer at Severance Hospital, Yonsei University Medical College from November 1995 to March 1996, and 96 control patients of non-ulcer dyspepsia (NUD) were studied by endoscopic biopsy of normal gastric tissue and cancer tissue. They also underwent the CLO (Delta West, Melbourne, Western Australia) test for Hp positivity and p53 immunohistochemical stain for p53 positivity. These data were analyzed for comparison with the clinicopathologic characteristics of gastric cancers. In conclusion, the differentiated group cancer had a significantly high Hp positivity and p53 positivity. There is a possibility that Hp infection and p53 tumor suppressor gene mutation might be significantly related in the gastric carcinogenic process of well- and moderately-differentiated adenocarcinomas, but further study is necessary to determine more direct clues on the carcinogenic roles of these factors.

The Overxpression of p53 in gestational Trophoblastic Disease and Normal Human Placenta / 대한부인종양콜포스코피학회잡지

Mutations in the tumor suppressor p53 gene are the most frequently observed genetic lesions in human cancers. It seems that wild type p53 does significant role on growth and differentiation of normal cells, Mutations and allelic loss of the p53 gene are thought to be a cause of tumor development and to be correlated with the prognostic factors in various human cancers such as breast, ovary and lung cancer. Mutant p53 proteins have a prolonged half-life and can be detected by immunohistochemistry. In case of GTD(gestational trophoblastic disease), although the mutation of p53 gene mutation was revealed to be very rare, the overexpression of p53 in immunohistochemical staining has been reported in wide range of discrepancy and its role or prognostic significance in GTD is uncertain. This study is performed to define the status of p53 overexpression in GTD and to evaluate the correlations between p53 overexpression and prognostic factors of GTD. THE RESULTS WERE AS FOLLOWS: 1. p53 overexpression was detected in none of normal placental tissue, in 58.3%(14/24) of hydatidiform mole, in 15%(6/8) of invasive mole, in 75%(3/4) of choriocarcinoma, and in 100%(1/1) of placental site trophoblastic tumor, and showed significant difference between normal placenta and GTD. We could not find any difference of the p53 overexpression between benign group(H-mole) of GTD and malignant one(invasive mole, choriocarcinoma, and placental site trophoblastic tumor) 2. In H-mole, low-risk group showed significantly higher prevalence of p53 overexpression than high-risk group did. In malignant group, there is no difference in the prevalence of p53 overexpression between early(FIGO stage I) and late(II- IV)stage-diseases, but the prevalence of p53 overexpression of low-risk group is slightly higher than that of high-risk group although we failed to find statistical significance. In conclusion, the high prevalence of p53 overexpression in GTD suggests that p53 may have a certain role in the pathogenesis of GTD or at least represent generalized DNA damage or genetic instability of GTD. And the higher prevalence of p53 overexpression in low-risk group suggests that accumulation of wild-type p53 may be related with favorable prognosis in GTD.