RESUMEN
The relationship between methylation abnormality and autoimmune pancreatitis (AIP)-a representative IgG4-related disease-has not yet been elucidated. We identified SKI might have a significant methylation abnormality in AIP through methylation array analysis using the Illumina Infinium Human Methylation 450K BeadChip array, and investigated the relationship of SKI with AIP clinicopathological features. The methylation rate of SKI was assessed by quantitative SYBR green methylation-specific PCR, and the degree of SKI expression in tissue specimens was assessed by immunohistochemistry in 10 AIP cases, 14 cases of obstructive pancreatitis area in pancreatic ductal adenocarcinoma (PDA) without a history of AIP, and 9 normal pancreas (NP) cases. The SKI methylation ratio was significantly lower in AIP than in PDA and NP. Additionally, the immunohistochemical staining-index (SI) score for SKI was significantly higher in AIP than NP, although there was no significant difference between AIP and PDA. There was a strong negative correlation between SI score and SKI methylation ratio, and between the serum concentrations of IgG4 and the SKI methylation ratio. There was a moderate positive correlation between the serum concentrations of IgG4 and SI. SKI is thought to be an oncogene indicating that SKI hypomethylation and carcinogenesis might be linked to AIP. Furthermore, the correlation between serum concentrations of IgG4 and SKI methylation levels suggest SKI might be involved in the pathogenesis of AIP. However, the role of SKI has not been clearly elucidated. Further studies are needed to understand further the function of SKI.
Asunto(s)
Enfermedades Autoinmunes/genética , Carcinoma Ductal Pancreático/genética , Proteínas de Unión al ADN/genética , Pancreatitis/genética , Regiones Promotoras Genéticas/genética , Proteínas Proto-Oncogénicas/genética , Anciano , Enfermedades Autoinmunes/inmunología , Enfermedades Autoinmunes/patología , Carcinoma Ductal Pancreático/inmunología , Carcinoma Ductal Pancreático/patología , Metilación de ADN , Femenino , Humanos , Inmunoglobulina G/sangre , Masculino , Persona de Mediana Edad , Páncreas/patología , Pancreatitis/inmunología , Pancreatitis/patología , Estudios RetrospectivosRESUMEN
OBJECTIVES: Autoimmune pancreatitis (AIP) is a representative IgG4-related and inflammatory disease of unknown etiology. To clarify mechanisms of carcinogenesis resulting from AIP, we focused on methylation abnormalities and KRAS mutations in AIP. METHODS: Six tumor suppressor genes (NPTX2, Cyclin D2, FOXE1, TFPI2, ppENK, and p16) that exhibited hypermethylation in pancreatic carcinoma were selected for quantitative SYBR green methylation-specific polymerase chain reaction in 10 AIP specimens, 10 pancreatic adenocarcinoma cases without history of AIP containing carcinoma areas (CAs) and noncarcinoma areas (NCAs), and 11 normal pancreas (NP) samples. KRAS mutation in codons 12, 13, and 61 were also investigated using direct sequencing. RESULTS: Hypermethylation events (≥10%) were identified in NPTX2, Cyclin D2, FOXE1, TFPI2, ppENK, and p16 in 1, 2, 2, 0, 2, and 0 CA cases, respectively, but not in these 6 candidate genes in AIP, NCA, and NP. However, the TFPI2 methylation ratio was significantly higher in AIP than NCA and NP. Direct sequencing results for KRAS showed no single-point mutations in AIP. CONCLUSIONS: These are the first studies characterizing methylation abnormalities in AIP. AIP's inflammatory condition may be related to carcinogenesis. Further study will elucidate methylation abnormalities associated with carcinogenesis in AIP.
Asunto(s)
Enfermedades Autoinmunes/genética , Metilación de ADN , Genes Supresores de Tumor , Pancreatitis/genética , Adenocarcinoma/genética , Adulto , Anciano , Anciano de 80 o más Años , Islas de CpG/genética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mutación , Neoplasias Pancreáticas/genética , Proteínas Proto-Oncogénicas p21(ras)/genéticaRESUMEN
A 77-year-old male with a long history of alcohol consumption and smoking was admitted for hoarseness and dysphagia. Computed tomography revealed thickening of the middle intrathoracic esophageal wall and multiple mediastinal lymph node swellings. Esophagogastroduodenoscopic examination disclosed an advanced-stage squamous cell carcinoma lesion in the middle intrathoracic esophagus with synchronous early stage Barrett's adenocarcinoma. The patient underwent endoscopic submucosal dissection for the adenocarcinoma followed by chemoradiation therapy for the squamous cell carcinoma. In spite of their common risk factors, the simultaneous manifestation of esophageal squamous cell carcinoma and Barrett's adenocarcinoma is extremely rare and requires further study.
Asunto(s)
Adenocarcinoma/diagnóstico por imagen , Esófago de Barrett/diagnóstico por imagen , Carcinoma de Células Escamosas/diagnóstico por imagen , Neoplasias Esofágicas/diagnóstico por imagen , Neoplasias Primarias Múltiples/diagnóstico por imagen , Adenocarcinoma/patología , Adenocarcinoma/cirugía , Anciano , Esófago de Barrett/patología , Esófago de Barrett/cirugía , Biopsia , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/terapia , Neoplasias Esofágicas/patología , Neoplasias Esofágicas/cirugía , Neoplasias Esofágicas/terapia , Carcinoma de Células Escamosas de Esófago , Esófago/patología , Humanos , Masculino , Neoplasias Primarias Múltiples/patología , Neoplasias Primarias Múltiples/terapia , Tomografía Computarizada por Tomografía de Emisión de Positrones , Factores de RiesgoRESUMEN
A 58-year-old Japanese man was diagnosed with differentiated adenocarcinoma of the stomach. Histological findings of the resected specimen revealed well- to moderately-differentiated tubular adenocarcinoma (tub1, tub2), 13 mm in diameter, which invaded into the submucosa (SM1, 300 µm) and lymphovascular lumen (ly1). Serum antibody against Helicobacter pylori (Hp) and the (13)C-urea breath test were negative, and there were no atrophic changes in the tumor-adjacent mucosa. The immunohistochemical analysis showed that gastric mucin (MUC5AC) was strongly positive and intestinal mucin (MUC2) was weakly and partially positive. According to these results, the final diagnosis of Hp-negative well-differentiated early gastric cancer was made.
Asunto(s)
Adenocarcinoma/patología , Disección , Mucosa Gástrica/patología , Proteínas de Homeodominio/metabolismo , Mucina 2/metabolismo , Neoplasias Gástricas/patología , Adenocarcinoma/metabolismo , Biomarcadores de Tumor/metabolismo , Factor de Transcripción CDX2 , Mucinas Gástricas/metabolismo , Gastroscopía , Helicobacter pylori , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Neoplasias Gástricas/metabolismo , Resultado del TratamientoAsunto(s)
Carcinoma de Células Escamosas/diagnóstico por imagen , Carcinoma de Células Escamosas/patología , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/patología , Pulmón/patología , Anciano , Biopsia , Carcinoma de Células Escamosas/cirugía , Femenino , Humanos , Neoplasias Pulmonares/cirugía , Tomografía Computarizada por Rayos XRESUMEN
The biological characteristics and roles of insulin-like growth factor II mRNA-binding protein 3 protein (IMP3) expression in small-intestinal adenocarcinoma were investigated. The value of IMP3 immunostaining in the diagnosis of small-intestinal epithelial lesions was also evaluated. Immunohistochemical expression of IMP3 in normal small-intestinal mucosa adjacent to adenoma and adenocarcinoma lesions, and inflamed duodenal and ileal mucosa was analyzed. Samples assessed were: duodenal ulcer (n=6), Crohn's disease (n=5), low-grade small-intestinal adenoma (n=10), high-grade small-intestinal adenoma (n=13), small-intestinal adenocarcinoma (n=23), lymph node metastases (LNM; n=7), and preoperative biopsies of small-intestinal adenocarcinoma (n=6). Immunohistochemical expression of Ki-67 and p53 was also analyzed in adenoma and adenocarcinoma samples. IMP3 was not expressed in normal epithelium, but weakly expressed in reparative epithelium. Meanwhile, increased IMP3 expression was associated with a higher degree of dysplasia in adenomas, higher T classification, LNM, Ki-67 positivity, histological differentiation, and lower 5-year disease-free survival, but not p53 expression in adenocarcinoma. IMP3 expression appears to be a late event in the small-intestinal carcinogenesis. Assessing the IMP3 staining pattern can be useful in the diagnosis of small-intestinal epithelial lesions when used in conjunction with other histological criteria.
RESUMEN
A total of 320 localized prostate cancer patients including 272 at low-risk and 48 at intermediate-risk were treated with permanent iodine-125 seed implants. Changes of lower urinary tract symptoms after the treatment were analyzed for one consecutive year using international prostate symptom score, quality of life (QOL) score and uroflowmetry. These patients did not have prostate hypertrophy or were not treated with any α1 blocker before the seed implant. Tamsulosin (0.2 mg/day) was prophylactically administered to all the patients for six months beginning the day after the seed implant. Both voiding and storage symptoms developed even in patients without any urinary symptoms before seed implant and worsened during the consecutive three months; and, QOL also worsened after seed implant. Lower urinary tract symptoms continued to be significantly severe for six months compared with that before the seed implant, then improved gradually to almost the initial level after one year. It seems to take longer for storage symptoms to diminish to the initial level compared with voiding symptoms. Neoadjuvant hormone therapy improved neither voiding nor storage symptoms in patients without prostate hypertrophy less than 40 ml in volume. In conclusion, a more effective α1 blocker or other potent prophylactic drug therapy should be used on the patients after seed implant because the disadvantage of seed implant is probably only urinary disturbance.
Asunto(s)
Braquiterapia/efectos adversos , Radioisótopos de Yodo/efectos adversos , Síntomas del Sistema Urinario Inferior/etiología , Neoplasias de la Próstata/diagnóstico por imagen , Antagonistas de Receptores Adrenérgicos alfa 1/uso terapéutico , Anciano , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Próstata/tratamiento farmacológico , Calidad de Vida , Radiografía , Sulfonamidas/uso terapéutico , TamsulosinaRESUMEN
A 61-year-old man had been followed up in another hospital under diagnosis of branch duct type IPMN for 4 years. Contrast-enhanced CT scan for regular check performed 3 months ago revealed no increase of IPMN and no pancreatic tumor. However, he complained of back pain after that, MRI was performed. It revealed a solid tumor in size of 25mm diameter at the head of pancreas. The tumor was apparent from IPMN in several imaging modalities. Pancreatoduodenectomy was performed under diagnosis of invasive ductal carcinoma concomitant with IPMN. Post-operative pathological findings revealed IPMN was adenoma with mild atypia, and solid tumor was diagnosed invasive ductal carcinoma with solitary minute liver metastasis.
Asunto(s)
Adenocarcinoma Mucinoso/patología , Carcinoma Ductal Pancreático/patología , Neoplasias Primarias Secundarias/patología , Neoplasias Pancreáticas/patología , Adenocarcinoma Mucinoso/diagnóstico por imagen , Carcinoma Ductal Pancreático/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Neoplasias Primarias Secundarias/diagnóstico por imagen , Neoplasias Pancreáticas/diagnóstico por imagen , Tomografía Computarizada por Rayos XRESUMEN
The possible involvement of immunoglobulin G4 (IgG4) in the pathogenesis of idiopathic sclerosing lesions has been suggested. In this study, a clinicopathologic analysis was performed to reveal characteristics of retroperitoneal fibrosis relating to IgG4. The study involved 17 patients with retroperitoneal fibrosis. Immunohistochemistry revealed numerous IgG4-positive plasma cell infiltrates in 10 cases (IgG4-related), but only a few positive cells in 7 cases (non-IgG4-related). All patients with IgG4-related retroperitoneal fibrosis were male, whereas all except 1 with unrelated lesions were female. Histologically, eosinophilic infiltration (>5 cells per high-power field) and obliterative phlebitis were commonly observed in IgG4-related lesions. Serologically, serum IgG and IgG4 concentrations were significantly higher in the IgG4-related cases, with the IgG4 concentrations all over 135 mg/dL (the upper limit of the normal range). Steroid therapy was performed in 13 cases, and was effective irrespective of IgG4. Three patients had recurrence during the follow up. Five of 10 IgG4-related cases had sclerosing lesions at other sites. The only tests that reliably distinguish the 2 groups were serum IgG4 levels or IgG4/IgG ratio in the plasma cells in a tissue biopsy. The only major clinical difference was the striking male predominance in IgG4-related cases. In conclusion, this study revealed that retroperitoneal fibrosis could be classified as IgG4-related or not. This distinction seems important to help better characterize the biology/pathogenesis of both groups and better predict the possibility of other IgG4-related processes at other anatomic sites.
Asunto(s)
Inmunoglobulina G/análisis , Células Plasmáticas/inmunología , Fibrosis Retroperitoneal/inmunología , Adulto , Anciano , Anticuerpos Antinucleares/sangre , Biomarcadores/sangre , Biopsia , Eosinofilia/inmunología , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Flebitis/inmunología , Células Plasmáticas/patología , Recurrencia , Fibrosis Retroperitoneal/complicaciones , Fibrosis Retroperitoneal/tratamiento farmacológico , Fibrosis Retroperitoneal/patología , Esteroides/uso terapéutico , Resultado del TratamientoRESUMEN
A 74-year-old male with advanced gastric cancer(cT3N1M0H0P0CY0, cStage III A)was treated with paclitaxel/ CDDP as neoadjuvant chemotherapy. Paclitaxel (80 mg/m(2)) and CDDP (25 mg/m(2)) were administered on days 1, 8 and 15 as one cycle. After the second course, a significant tumor reduction was obtained. Total gastrectomy, splenectomy, and D2 type nodal dissection were performed. The histological diagnosis revealed complete disappearance of cancer cells in the stomach and all of the lymph nodes, a so-called pathologically complete response. The patient has now been in good health without any recurrence for 9 months after surgery. This case suggests that neoadjuvant chemotherapy with paclitaxel/CDDP is a potential regimen for advanced gastric cancer.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Cisplatino/uso terapéutico , Terapia Neoadyuvante , Paclitaxel/uso terapéutico , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/patología , Anciano , Endoscopios Gastrointestinales , Gastrectomía , Humanos , Masculino , Estadificación de Neoplasias , Neoplasias Gástricas/diagnóstico por imagen , Neoplasias Gástricas/cirugía , Tomografía Computarizada por Rayos XRESUMEN
The ulcer-associated cell lineage (UACL) induced at the site of ileac chronic ulceration in Crohn's disease has been reported to show histological differentiation resembling gastric pyloric mucosa. To clarify the significance of homeobox gene-encoded transcription factors in the formation of the UACL in Crohn's disease, we investigated the immunohistochemical expression of gastrointestinal mucins (MUC5AC for gastric surface mucous cells; MUC6 for gastric gland mucous cells, and MUC2 for intestinal goblet cells) and homeobox gene-encoded transcription factors (CDX-2 for intestinal mucosa and PDX-1 for pyloric mucosa) in the UACL. The analysis was undertaken on ileal mucosa obtained from ileal resections performed in 19 patients with active Crohn's disease of the small bowel. The UACL was observed in nine patients. In the UACL, expression of mucous cells with a foveolar-structure showed immunoreactivity to MUC5AC, and the mucous cells with a glandular structure showed immunoreactivity to MUC6, and the expression of MUC2 was decreased. In addition, we detected the decreased expression of CDX-2 along with the increased expression of PDX-1 in the UACL. The UACL showed histological differentiation simulating gastric pylori mucosa. The down-regulation of CDX-2 and the up-regulation of PDX-1 could be an important mechanism in the induction of the UACL.
Asunto(s)
Enfermedad de Crohn/metabolismo , Enfermedad de Crohn/patología , Proteínas de Homeodominio/metabolismo , Mucinas/análisis , Transactivadores/metabolismo , Factor de Transcripción CDX2 , Mucosa Gástrica/química , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patología , Histocitoquímica , Proteínas de Homeodominio/análisis , Humanos , Íleon/química , Íleon/metabolismo , Inmunohistoquímica , Mucosa Intestinal/química , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patología , Metaplasia , Mucina 5AC , Mucina 2 , Mucina 6 , Mucinas/metabolismo , Transactivadores/análisisRESUMEN
The predominantly young woman-orientated systemic lupus erythematosus (SLE) is a disease that involves an extremely complicated and multifactorial interaction of various genetic and environmental factors. Crystalline silica (Si) may act as an immunoadjuvant to increase secretions of inflammatory endogenous substances and antibody production. In addition, previous studies have suggested that exposure to Si may induce SLE. Although the biologic mechanism of Si in SLE is unclear, defective apoptosis leading to the prolonged survival of pathogenic lymphocytes was thought to be one of mechanisms of Si-associated SLE (sSLE). In the present study, a rare case of an elderly man suffering from sSLE responded well to glucocorticoid therapy. The present findings were reviewed with reference to previous literature.
Asunto(s)
Pulmón/patología , Nefritis Lúpica/etiología , Dióxido de Silicio/efectos adversos , Silicosis/complicaciones , Anciano , Glucocorticoides/uso terapéutico , Humanos , Pulmón/diagnóstico por imagen , Nefritis Lúpica/tratamiento farmacológico , Masculino , Metilprednisolona/uso terapéutico , Prednisolona/uso terapéutico , RadiografíaRESUMEN
OBJECTIVE: To evaluate the initial results of brachytherapy for prostate cancer with permanent iodine-125 implant in Japan. METHODS: The results obtained with brachytherapy in the initial 100 Japanese patients treated at Nagano Municipal Hospital were reviewed. Patients with a prostate-specific antigen (PSA) level of less than 10 ng/mL and a Gleason's scores of 5, 6, 3 + 4 were classified as having a low risk of recurrence. Patients with a PSA level of 10-20 ng/mL and/or a Gleason's score of 4 + 3 were classified as having an intermediate risk for recurrence. Seventy-eight of the low-risk patients and 19 of the intermediate-risk patients were treated by seed implants alone, or seed implants combined with preceding external radiation, respectively. A total of 53 patients received neoadjuvant hormone therapy. The efficacy and morbidity of brachytherapy were investigated using the serum PSA, International Prostate Symptom Score, quality of life score and uroflowmetry data. RESULTS: The average V100 and D90 obtained by post-implant dosimetry was 94.3 and 113.7%, respectively. Serum PSA decreased gradually after treatment, although it had still not reached a nadir after 1 year. There was little difference of the PSA level between the patients with and without neoadjuvant hormone therapy even at 1 year after seed implantation. There were no PSA biochemical failure or clinical recurrence during the follow-up period. Voiding symptoms worsened until 3 months after treatment, and then gradually improved. Acute urinary retention occurred transiently in one patient (1%). Rectal bleeding and severe diarrhea did not occur. CONCLUSION: Brachytherapy is a feasible and effective option for the treatment of prostate cancer in Japanese men. Brachytherapy may have a different effect in Japanese patients with respect to voiding symptoms. Urinary retention was rare, but voiding symptoms were persistent in Japanese patients. Neoadjuvant hormone therapy deserves investigation to determine whether it can achieve better results, especially in patients with an intermediate risk.
Asunto(s)
Braquiterapia , Radioisótopos de Yodo/administración & dosificación , Neoplasias de la Próstata/radioterapia , Anciano , Anciano de 80 o más Años , Humanos , Japón , Masculino , Persona de Mediana EdadRESUMEN
The prevalence of tuberculosis in small solitary lesions of the lung obtained by video-assisted thoracoscopic surgery (VATS) is still unclear. Of 103 lung lesions resected by VATS in 98 patients (47 men, 51 women), 19 were identified macroscopically as inflammatory changes, 78 were neoplastic, and 6 were undefined. Presumptive diagnosis based on microscopic analysis of fresh specimen smears treated with Papanicolaou stain was performed in 19 lesions. Of these, 11 lesions had epithelioid cells, granulomas with caseous necrosis and Langerhans-type giant cells. The 6 undefined lesions were non-inflammatory benign changes. Isolation and identification of tuberculosis were based on microscopic findings of fresh material smears and sections of fixed specimens stained with Ziehl-Neelsen's dye, cultivation using egg-based Ogawa medium, and in situ hybridization between polymerase chain reaction (PCR) products of each of the 11 lesions and specific DNA sequences for Mycobacterium tuberculosis, M. avium, and M. intracellulare. Of these 11 lesions, M. tuberculosis was confirmed in one (0.96%) by PCR and M. avium was confirmed in four by culture and PCR. Of the 78 malignant lesions, final pathologies were primary lung cancer (n=59, 70.2%) and pulmonary metastatic cancer (n=19, 22.6%). The most frequent primary malignant cancer was adenocarcinoma, which was found in 19 men and 28 women in the present study. Eight lesions in 8 men were squamous cell carcinomas. The results of the present study suggested that even though the prevalence of lung tuberculosis is low, attention should be paid to the presence of M. tuberculosis in specimens obtained by VATS.
Asunto(s)
Nódulo Pulmonar Solitario/microbiología , Tuberculosis Pulmonar/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Diagnóstico Diferencial , Femenino , Granuloma del Sistema Respiratorio/diagnóstico , Humanos , Neoplasias Pulmonares/diagnóstico , Masculino , Persona de Mediana Edad , Cirugía Torácica Asistida por VideoAsunto(s)
Neoplasias del Colon/patología , Neoplasias del Yeyuno/patología , Linfoma de Células B de la Zona Marginal/patología , Neoplasias Primarias Múltiples/patología , Neoplasias Gástricas/patología , Neoplasias del Colon/cirugía , Terapia Combinada , Humanos , Neoplasias del Yeyuno/cirugía , Linfoma de Células B de la Zona Marginal/terapia , Masculino , Persona de Mediana Edad , Neoplasias Primarias Múltiples/terapia , Neoplasias Gástricas/radioterapiaAsunto(s)
Adenocarcinoma Mucinoso/etiología , Adenocarcinoma Papilar/etiología , Ampolla Hepatopancreática/anomalías , Carcinoma Ductal Pancreático/etiología , Conductos Pancreáticos/anomalías , Neoplasias Pancreáticas/etiología , Adenocarcinoma Mucinoso/patología , Adenocarcinoma Papilar/patología , Anciano , Carcinoma Ductal Pancreático/patología , Femenino , Humanos , Neoplasias Pancreáticas/patologíaAsunto(s)
Neoplasias de los Conductos Biliares/diagnóstico , Conductos Biliares Extrahepáticos , Carcinoma de Células Pequeñas/diagnóstico , Anciano , Neoplasias de los Conductos Biliares/diagnóstico por imagen , Neoplasias de los Conductos Biliares/cirugía , Carcinoma de Células Pequeñas/diagnóstico por imagen , Carcinoma de Células Pequeñas/cirugía , Colangiopancreatografia Retrógrada Endoscópica , Femenino , Humanos , Tomografía Computarizada por Rayos X , UltrasonografíaRESUMEN
BACKGROUND: Although it is believed that p53 suppressor gene mutations, compared with mutations in the K-ras oncogene, occur at a later stage of colorectal tumorigenesis, the distribution of these genetic alterations at an early stage remains poorly characterized. METHODS: The authors analyzed the immunoreactivity for p53 protein (p53 protein expression), which reflects the functionally altered p53 gene, and K-ras mutations at codons 12 in 68 colorectal adenomas with both low-grade and high-grade dysplasia obtained from 62 patients. RESULTS: The prevalence of p53 positive immunostaining was significantly greater compared with the prevalence of K-ras mutations both in low-grade dysplasia and in high-grade dysplasia. Twenty-two adenomas (32.3%) showed positive immunostaining for p53 protein in high-grade dysplasia and also were positive for p53 in surrounding low-grade dysplastic tissues; 20 adenomas (29.4%) showed positive immunostaining for p53 protein in high-grade dysplasia and were negative for p53 in surrounding low-grade dysplastic tissues; 8 adenomas (11.7%) showed negative immunostaining for p53 protein in high-grade dysplasia and were positive for p53 in surrounding low-grade dysplastic tissues; and 18 adenomas (26.4%) showed negative immunostaining for p53 protein in both high-grade dysplasia and in surrounding low-grade dysplastic tissues. On the whole, a significant difference (P < 0.05) was seen in the frequency of p53 positive immunostaining between low-grade dysplasia and high-grade dysplasia (44.1% and 61.8%, respectively) but not in that of K-ras mutations (20.3% and 23.4%, respectively). CONCLUSIONS: The results of this study suggest that mutation of the p53 suppressor gene occurs earlier in the adenoma-carcinoma sequence than K-ras mutation, providing a clue for further understanding of the role of the p53 gene in the early stage of colorectal tumorigenesis.