p53 codon 72 polymorphism in patients affected with ulcerative colitis

Background The p53 tumor suppressor protein plays a fundamental role in maintaining genomic integrity through its ability to arrest the cell cycle in G1 and induce apoptosis. The proapoptotic activity of p53 seems to be strictly related to proline-rich regions, homologous to the SH3 binding domain. In the literature, reported data suggest a role for polymorphism at codon 72 of p53 in the predisposition to neoplastic transformation, although the results are still controversial. In this study, we investigated Arg72Pro polymorphism of p53 and related this polymorphism to clinical parameters in patients affected with ulcerative colitis (UC). Methods We studied 243 consecutive outpatients affected with well-established UC. The control group comprised 142 healthy blood donors, with age and sex comparable to those of the patients. Results p53 Pro/Pro was significantly related to the clinical course and duration of disease (odds ratio, 55.8 and 8.8, respectively). Nineteen of 24 patients with Pro homozygosity had a duration of disease >7 years. In contrast, 87 of 123 patients with Arg/Arg had short-standing UC (≤7 yrs) and 66 of 96 with Arg/Pro had short-standing UC (χ-squared, 22.86; P < 0.0001). Thirty-four of 243 patients affected with UC had a positive family history for colorectal carcinoma (CRC). In those patients p53, Pro/Pro was significantly related to a family history of CRC (odds ratio, 38.1). Conclusions These preliminary data suggest that polymorphism at codon 72 of the p53 gene influences the clinical course of UC, with continuous disease associated with p53 Pro homozygosity.     

Relation between K-ras codon 12 mutation and p53 protein overexpression in gallbladder cancer and biliary ductal epithelia in patients with pancreaticobiliary maljunction

It is well known that the incidence of biliary cancer is higher in patients with pancreaticobiliary maljunction (PBM) than in individuals without PBM. However, the relationship between PBM and the carcinogenesis remains unclear. The purpose of the present study was to examine histopathologic changes in the mucosa of the gallbladder and bile duct in patients with PBM, and to investigate K‐ras oncogene mutation and overexpression of p53 protein in the mucosa. We examined 47 surgical specimens of gallbladder and 36 surgical specimens of bile duct obtained from 48 patients with PBM. The 48 patients were divided into three age groups: group A (0—3 years), group B (4—39 years), and group C (40 years or more). Investigation of K‐ras mutation and overexpression of p53 protein was performed using an enriched polymerase chain reaction (PCR) and enzyme‐linked mini‐sequence assay (ELMA), and by the streptavidin‐biotin (SAB) method, using DO‐7 antibodies, respectively. Hyperplastic changes in the gallbladder mucosa were observed in patients in the three groups. However, metaplastic or dysplastic changes were observed in the mucosa of only groups B and C. K‐ras gene mutation in the gallbladder mucosa was found in 18.8% of the hyperplastic mucosae in group B and in 20% in group C. The mutation was found in 33.3% of lesions with metaplastic change associated with hyperplastic changes and in 25% of lesions with dysplastic changes in group C. No mutation was observed in the non‐cancerous mucosae of gallbladders and bile ducts without congenital dilatation of the bile duct. Overexpression of p53 protein was observed only in carcinoma of the gallbladder; in seven of nine advanced carcinomas and in two of three carcinomas in situ. We concluded that the mucosal epithelia of the biliary system in patients with PBM showed a high frequency of gene mutations and the carcinogenesis appeared in involve a multistage process of mutation in the K‐ras gene and the p53 supressor gene.     

p53 expression in gastric mucosa with Helicobacter pylori infection

Expression of p53 was examined immunohistochemically in the Japanese monkey model with Helicobacter pylori infection of the gastric mucosa to investigate the association between H. pylori infection and gastric carcinogenesis for a period of 4 years. In the course of these observations, from 3 years after H. pylori inoculation, nuclear staining for p53 was seen in the glandular cells of the mucosa infected with H. pylori, especially in the neck region of the glands. There was a gradual increase in the number of immunopositive cases among the infected animals. Three years after inoculation, three out of six cases, and 4 years after inoculation, four out of six cases exhibited positive staining for p53. Before inoculation, and up to 2 years after inoculation, the infected group showed no immunoreaction for p53. The non-infected group likewise displayed no immunostaining for p53 through 4 years of observation. These results suggest that p53 alterations occur in the H. pylori-infected gastric mucosa and that H. pylori infection may play an important role in gastric carcinogenesis.     

Expression of the p53 homologue p63alpha and DeltaNp63alpha in the neoplastic sequence of Barrett's oesophagus: correlation with morphology and p53 protein

BACKGROUND: While loss of p53 function is a key oncogenic step in human tumorigenesis, mutations of p53 are generally viewed as late events in the metaplasia-dysplasia-adenocarcinoma sequence of Barrett's oesophagus. Recent reports of a series of genes (p63, p73, and others) exhibiting close homology to p53 raise the possibility that abnormalities of these p53 family members may exert their influence earlier in the sequence. AIM: Following recent characterisation of expression of p63 and a major isoform DeltaNp63 by generation of an antiserum that recognises p63 isoforms, but not p53, our aim was a comparative study of expression of p63 protein and p53 protein in a morphologically well defined biopsy series representative of all stages of the metaplasia-dysplasia-carcinoma sequence in Barrett's oesophagus. METHODS: A series of 60 biopsy cases representing normal oesophagus through to invasive adenocarcinoma were stained, using immunohistochemistry, with antibodies to p63 and p53. All biopsies derived from patients with endoscopic and histopathological substantiation of a diagnosis of traditional/classical Barrett's oesophagus. RESULTS: There was exact concordance in p53 and p63 expression in more advanced forms of neoplasia, high grade dysplasia, and invasive adenocarcinoma, while p63, but not p53, was detected in the proliferative compartment of some non-neoplastic oesophageal tissue, in both squamous mucosa and in the non-neoplastic metaplastic glandular epithelium. CONCLUSIONS: In neoplastic Barrett's oesophagus there is upregulation of both p63 and p53 while p63 isoforms may well have an important role in epithelial biology in both non-metaplastic and metaplastic mucosa of the oesophagus. While abnormalities of p53 function represent an indisputable and critical element of neoplastic transformation, other closely linked genes and their proteins have a role in both the physiology and pathophysiology of the oesophageal mucosa.     

Overexpression of p53 in hepatocellular carcinomas: A clinicopathological and prognostic correlation

Abstract Overexpression of the p53 tumour suppressor gene is one of the most common abnormalities in primary human cancers and appears to be a result of point mutation within a highly conserved region of the gene with subsequent encoding for a mutant, more stable protein. In this study, 71 surgically resected hepatocellular carcinomas (HCC) were examined to study the expression of the p53 gene, its relation with clinicopathological parameters and its prognostic significance. Using immunohistochemical detection for mutant p53 protein with monoclonal antibody PAb1801, p53 overexpression was found in 22 tumours (31%) but in none of the non-tumorous liver specimens. Overexpression of p53 was more frequent in tumours with poor cellular differentiation ( P = 0.01), in tumours > 5 cm in diameter ( P = 0.05), and in those with giant cells present ( P = 0.03) and, less significantly, of massive type of Eggel's classification ( P = 0.06). It did not have any significant correlation with hepatitis B or C status, background liver disease or serum α-fetoprotein levels, nor was it related to tumour invasiveness (venous permeation, direct liver invasion and tumour microsatellite formation). In addition, the presence of p53 mutant protein did not influence tumour recurrence or patients' survival rates. The data suggested that p53 mutation in HCC was associated with a later stage of oncogenesis. However, it was not apparently related to tumour invasiveness/aggressiveness and prognosis.     

Expression of p53 in adenocarcinoma of the gallbladder and bile ducts

Abstract: Point mutation of the p53 tumor suppressor gene appears to be an important event in tumor development and progression, and overexpression of the p53 gene product has been widely studied in a variety of neoplasms. Some point mutations of the p53 gene lead to an increase in half-life in the gene product, which accumulates in the nucleus and can be detected by immunohistochemical means. We studied overexpression of p53 protein in specimens from 12 patients with adenocarcinoma of the gallbladder, two gallbladders with epithelial dysplasia without carcinoma, eight carcinomas of the common bile duct, 13 hilar cholangiocarcinomas, and six peripheral cholangiocarcinomas. The monoclonal antibody Ab-2 (Oncogene Science) was used in conjunction with citrate microwave antigen retrieval. Nuclear staining was scored as positive (graded 1 to 3, depending on number of positive nuclei) or negative. Overexpression of p53 protein was present in 7/12 (58%) gallbladder carcinomas, and was seen more often in moderately or poorly differentiated tumors. Intramucosal carcinoma adjacent to invasive carcinoma was positive in three cases, although fewer cells stained than in the carcinoma. Two cases of low-grade dysplasia not associated with carcinoma were negative. Expression of p53 was not an independent prognostic factor when survival was related to grade and stage of tumor. Three of eight (38%) common bile duct carcinomas and 5/13 (38%) hilar cholangiocarcinomas were positive for p53. Slightly fewer (2/6, 33%) peripheral cholangiocarcinomas were positive. No difference in survival relative to p53 expression was demonstrated.     

Immunohistochemical demonstration of the p53 tumour suppressor gene product in cancer of the pancreas and chronic pancreatitis

The p53 tumour suppressor gene and its protein products after point mutations are currently attracting wide attention in the investigation of human tumours. In this study we present the findings on percutaneous pancreatic biopsies of 82 cases after routine processing and immunostaining for the polyclonal p53 antibody CM1, an antibody directed against both wild and mutant forms of p53 protein. There were 51 carcinomas, 5 islet cell tumours, 16 cases of chronic pancreatitis (including one with atypical ductal epithelium) and seven histologically normal pancreatic biopsy specimens. None of the seven normal cases showed any definite nuclear immunostaining for p53. Thirty-two (63%) of the pancreatic adenocarcinomas showed moderate to intense immunoreactivity. Of the 16 cases of chronic pancreatitis, 11 were negative and three showed equivocal immunostaining. The one case with ductal epithelial atypia showed mild to moderate immunoreactivity. All islet cell tumours were negative. The expression of the p53 gene, therefore, appears increased in the majority of pancreatic adenocarcinomas while this is not observed in chronic pancreatitis or normal pancreatic tissue. Nuclear immunoreactivity for p53 protein may represent mutant forms because of the short half-life of the wild-type protein. The lack of p53 expression in some cases of pancreatic adenocarcinoma may be due to different types of mutant proteins not detectable by the CM1 antibody. Nuclear immunoreactivity to the p53 protein in pancreatic biopsy is more suggestive of a malignant tumour than chronic pancreatitis.     

p53 Gene mutations and overexpression of p53 product in cancerous and noncancerous biliary epithelium in patients with pancreaticobiliary maljunction

To investigate the molecular mechanisms of the high incidence of carcinogenesis in the biliary epithelium of patients with pancreaticobiliary maljunction, we examined p53 gene mutations, loss of heterozygosity of p53, and overexpression of p53 gene product in the cancerous and noncancerous biliary epithelium of 27 patients with pancreaticobiliary maljunction. Mutations of the p53 gene were examined by polymerase chain reaction-single strand conformation polymorphism and a direct sequencing method. Loss of heterozygosity of the p53 gene was determined using a double-targeted fluorescence in situ hybridization method. Expression of p53 gene product was examined using immunohistochemical staining. Mutations of the p53 gene were found in 4 of 5 biliary carcinomas (80%) and in 10 of 26 noncancerous biliary lesions (38.5%). Point mutations of the p53 gene were detected at codons 207, 212, and 217 on exons 5 through 8. The incidence of p53 gene mutations on exons 5, 6, 7, and 8 was 12.9%, 36.4%, 0.0%, and 13.8%, respectively. Loss of heterozygosity of p53 was shown in 72% of the cells obtained from the cancerous lesion, and in an average of 14% obtained from the noncancerous lesions. Overexpression of p53 protein was found in 57.1% of carcinoma, and in 31.3% of the noncancerous lesions. These results suggest that p53 gene mutations are involved in the carcinogenesis of biliary epithelium in patients with pancreaticobiliary maljunction.     

A High Degree of Aneuploidy,Loss of p53 Gene,and Low Soluble p53 Protein Serum Levels Are Detected in Ulcerative Colitis Patients

PURPOSE The causes for the increased risk of colorectal cancer associated with ulcerative colitis have not been fully defined. Colonic tissue of ulcerative colitis patients was examined for changes in chromosome-17-centromere copy number, loss of the p53 gene, and alterations in serum levels of the 53-kDa protein. This study was performed under the assumption that these molecular events correlate with ulcerative colitis status and duration.METHODS Ulcerative colitis patients (n = 42) and healthy controls (n = 37) participated in the study. All participants were histopathologically and medically diagnosed. The stage of ulcerative colitis patients was stratified according to increasing risk factors for the development of colorectal cancer: left-sided colitis, pancolitis, sclerosing cholangitis, and dysplasia-associated lesions or masses. Changes in centromere number of chromosome 17 alone or in association with changes in copy number of the p53 gene were analyzed in colon tissue biopsies by fluorescence in situ hybridization. Serum p53 level was determined in blood samples by immunoprecipitation followed by separation using high-pressure liquid chromatography.RESULTS Changes in chromosome 17 and p53 copy number and lower levels of serum p53 protein in ulcerative colitis patients directly correlated with colorectal cancer risk factors. All values significantly differed from controls. Significant direct correlations were obtained for ulcerative colitis disease duration, levels of p53 in the serum, and extent of aneuploidy.CONCLUSIONS We demonstrate that in the colonic mucosa of ulcerative colitis patients, high levels of genomic instability, changes in p53 gene copy number, and lower levels of p53 in the serum directly correlate with the extent of disease duration and increased risk factors for colorectal cancer. Any of the measurements described herein can provide an acceptable prognostic tool in the assessment of colorectal cancer risk in ulcerative colitis patients.     

p53 allele deletion and protein accumulation occurs in the absence of p53 gene mutation in T-prolymphocytic leukaemia and Sezary syndrome

In a series of 24 patients with chronic T-lymphoid disorders [13 T-prolymphocytic leukaemia (T-PLL) and 11 Sezary syndrome] we have studied (i) chromosome 17p abnormalities and p53 allele deletion by fluorescence in situ hybridization; (ii) mutation in the exons of the p53 gene by direct DNA sequencing; and (iii) p53 protein expression by immunocytochemistry and, in some cases, also by flow cytometry with DO-1, a monoclonal antibody to the p53 protein. The study revealed p53 deletion and accumulation of p53 protein in the absence of mutation in the exons that included the hot-spots and differs from that described in B-prolymphocytic leukaemia. Seven T-PLL and five Sezary syndrome patients had p53 overexpression, and five T-PLL and nine Sezary syndrome patients showed p53 deletion. Although the majority of cases with p53 accumulation had p53 deletion, the proportion of cells with the deletion did not correlate with the proportion of cells positive for p53 expression. Two cases of T-PLL showed strong p53 expression in the absence of p53 deletion, and one case of Sezary syndrome with p53 deletion in 97% of cells did not express p53. These findings suggest that a non-mutational mechanism exists for the accumulation of p53 protein in these T-cell disorders. The oncogenic effect of the accumulating wild-type protein has been reported in other malignancies. Whether haploidy resulting from p53 deletion contributes to this mechanism has yet to be determined. Alternatively, the frequent loss of the p53 gene could be associated with the deletion of an adjacent gene, which could be involved in the pathogenesis of these diseases.     

HSP60和p53在胃癌中的表达及意义

[目的]研究热休克蛋白60(HSP60)和p53在胃癌组织中的表达,并分析与胃癌临床病理特征的关系。[方法]采用免疫组化SABC法检测48例胃癌组织和14例正常胃黏膜中HSP60和p53的蛋白表达。[结果]胃癌组织中HSP 60和p53蛋白表达阳性率分别为81.3%、68.9%;HSP60在胃癌中表达与肿瘤分化程度及增殖能力有关(P0.05);p53蛋白在胃癌中表达与肿瘤大小、部位、浸润深度、淋巴结转移和肿瘤增殖能力有关(P0.05);HSP60与p53的表达无相关性。而HSP60在正常胃黏膜中有弱阳性表达(7.1%),在正常胃黏膜中未见p53表达。[结论]HSP60和p53表达与胃癌生物学行为有关,在胃癌的发生、发展过程中发挥着重要的作用。     

p53 gene mutations in soft-tissue sarcomas-correlations with p53 immunohistochemistry and DNA ploidy

The significance ofp53 mutations in a group of 67 soft-tissue tumors was examined using single-strand conformation polymorphism and direct sequencing analysis. Molecular findings were correlated with immunohistochemical detection of thep53 protein and DNA ploidy status. Mutations of thep53 gene were detected in 13 (19.5%) out of 67 cases of soft-tissue tumors. Only there were localized outside the conservative regions of thep53 gene. Six mutations were described for the first time in these tumors. Most of the mutations were point mutations in exons 5–8 and, in one case, a deletion at the 3-splice site of exon 5 could be demonstrated. There was no significant correlation between the occurrence ofp53 mutations and the histological grade, although a high number of mutations were defined in poorly differentiated tumors (grade 3). Molecular finding of ap53 gene mutation and immunohistochemical detection ofp53 expression did not correlate, which may be due to the high percentage of nonsense mutations in our study (50%). We confirm that only DNA sequencing allows a unique identification and differentiation of mutations in thep53 gene. Other factors may be responsible for the detection ofp53 protein in many cases. Histological grade correlated with aneuploidy. The frequency of mutations observed was in accordance with values quoted in the literature. Generally,p53 mutations andp53 overexpression are more likely to represent a late event in the oncogenesis of soft-tissue tumors.     

胃复春对胃癌癌前病变的治疗及对p21ras、p53表达的调节作用研究

目的：研究胃复春片对胃黏膜中、重度异型增生的治疗作用及对P21^ras、P53蛋白表达的调节作用，探讨其逆转胃癌癌前病变的治疗价值及机制。方法：内镜下病理活检证实为中、重度异型增生患者共58例，随机分为胃复春治疗组32例，维酶素对照组26例。治疗前后比较临床疗效，镜下改变，病理改变及胃黏膜固定部位活检标本P21^ras、P53蛋白S-P法免疫组化染色变化情况。结果：胃复春组临床症状的总有效率81．25％，内镜下改变总有效率71．88％，病理学改变总有效率65．63％，均优于维酶素对照组(分为53．85％、46．15％、34．61％)。P21^ras、P53蛋白在中、重度异型增生组织中有过度表达，胃复春能使其表达明显减弱。结论：胃复春对胃黏膜中、重度异型增生有良好的治疗作用，能促进病变胃黏膜的逆转，并对P21^ras、P53蛋白的表达有一定的调节作用，降低癌变危险性，可用于胃癌癌前病变的治疗。     

Screening for dysplasia and TP53 mutations in closed rectal stumps of patients with ulcerative colitis or Crohn disease

Background: Patients who undergo colectomy due to intractable chronic inflammatory bowel disease (IBD) may keep a closed rectal stump for several years, which may be at increased risk of malignant transformation owing to residual inflammatory activity. We examined a hospital series of patients with ulcerative colitis or Crohn colitis to describe the clinical, endoscopical and histological features of the closed rectal stump and to screen for dysplasia and mutations in the TP53 tumour suppressor gene. Methods: During rigid proctoscopy, rectal mucosal biopsy specimens and rectal lavage fluid were collected from 42 patients. Biopsy specimens were examined histologically, and genomic DNA extracted from frozen biopsies and lavage fluid was analysed for mutations in TP53 exons 4–9. Results: The median disease duration was 8.5 years (range 1.3–34 years). No endoscopic or histological signs of dysplasia or carcinoma were seen and no mutations in the TP53 gene were detected in any biopsy or lavage fluid specimens. Histological moderate to severe mucosal inflammation was present in 78% (33/42) of the patients, however, and rectal stump involution was noted in 43% (18/42). Conclusion: No signs of malignancy or premalignant degeneration were detected in this prospective series of IBD patients with a closed rectal stump. Although this is reassuring for patients, the presence of moderate to severe inflammation in the majority of rectal stumps indicates a role for adjuvant molecular markers to improve colorectal cancer surveillance on this subgroup of IBD patients.     

肝细胞癌基因P53异常的研究

目的：分析我国重庆地区肝细胞癌Ｐ５３基因失活机制及突变谱。方法：采用ＰＣＲ—ＲＦＬＰＰＣＲＳＳＣＰ和ＰＣＲ直接测序技术对来自我国重庆地区２８例肝细胞癌Ｐ５３抑癌基因结构异常进行了分析。结果：６１．５１％的肝癌存在ｐ５３的杂合缺失：５０％肝癌伴有ｐ５３基因突变，其突变模式为突普通散在于５６７和８外显子，其中第７外显子２４９们密友情子突弯率最高（２１％）；具有突变的肝癌多同时伴夺缺失。伴有ｐ５３基因结构异常的肝癌均属进展期。结论：我国重庆地区肝癌存在Ｐ５３基因结构异常，Ｐ５３基因结构异常，ｐ５３基因突变模式反映了该地区肝癌发生可能与肝炎病互和黄贡互素两种因素及其相互作用有关；ｐ５３基因结构异常属肝癌晚期事件，可能参加与肝癌的进展过程。     

血清降钙素原和C-反应蛋白在评价溃疡性结肠炎病情中的临床价值

[目的]探讨血清降钙素原(PCT)和C-反应蛋白(CRP)在评价溃疡性结肠炎病情中的临床价值。[方法]检测120例溃疡性结肠炎患者(病例组)和30例健康体检者(正常对照组)外周血PCT和CRP水平。[结果]病例组缓解期、活动期患者PCT水平分别为(1.56±0.36)μg/L、(6.57±2.96)μg/L,均明显高于正常对照组[(0.33±0.16)μg/L],P0.01;病例组缓解期、活动期CRP水平分别为(6.78±3.85)mg/L、(23.46±12.53)mg/L,均明显高于正常对照组[(0.68±0.23)mg/L],P0.01;活动期患者PCT、CRP水平缓解期患者(P0.01)。病例组轻度、中度、重度病情患者PCT水平分别为(3.64±1.78)、(5.67±2.75)、(8.96±1.86)μg/L,CRP水平分别为(8.75±3.64)、(22.78±6.57)、(31.45±11.34)mg/L;中度、重度病情患者的PCT、CRP水平均明显高于轻度者(P0.01),重度病情患者PCT、CRP水平均明显高于中度者(P0.01)。[结论]血清PCT和CRP水平可能成为评价溃疡性结肠炎病情活动及严重程度的辅助指标。     

Telomere shortening in the colonic mucosa of patients with ulcerative colitis

Telomere length in human somatic cells gradually decreases with the number of cell divisions and is regarded as a marker of somatic cell turnover. Mucosal cells of the affected colon show rapid turnover in individuals with active ulcerative colitis (UC). Telomere length was determined by Southern blot analysis of terminal restriction fragments (TRFs) from the colonic mucosa of 17 patients with UC in remission, two of whom showed dysplasia, and 17 control subjects without colitis. For each individual, mean TRF length was compared between rectal mucosa and unaffected cecal mucosa. The mean TRF length of the rectal mucosa was significantly less than that of cecal mucosa in UC patients (7.87 ± 0.36 kb versus 8.77 ± 0.21 kb; P = 0.0015, Wilcoxon signed rank test), whereas no significant difference was detected in the control subjects. The extent of telomere shortening was 10.6 ± 3.35% in UC patients, compared with 0.8 ± 0.64% in noncolitis controls (P = 0.0024, Mann-Whitney U-test). Four UC patients, two of whom had dysplasia, showed telomere shortening of more than 20% in the rectal mucosa. These observations suggest that telomere shortening in the colonic mucosa of individuals with UC may represent the history of mucosal inflammation during disease of long duration, and that it may contribute to aneuploidy in UC. (Received May 6, 1997; accepted Sept. 26, 1997)