True carcinosarcoma of the esophagus

Most esophageal carcinosarcomas are diagnosed as so-called carcinosarcoma, in which individual elements may be derived from a single common ancestor cell, and there have been a few reports describing true carcinosarcoma originating from two individual stem cells. We describe a case of esophageal carcinosarcoma exhibiting neoplastic osteoid formation. Immunoreactivity for vimentin and p53 was limited to only the sarcomatous component and was absent in the carcinomatous component. Furthermore, a point mutation in exon 7 of the p53 gene was observed only in the sarcomatous component. Both sarcoma and carcinoma cells distinctively metastasized to different lymph nodes. These observations led us to diagnose the esophageal tumor as a true carcinosarcoma.     

Immunohistochemical and molecular analysis of giant cell carcinoma of the pancreas: a report of three cases

We performed molecular biological studies as well as immunohistochemical analysis of three cases of giant cell carcinoma of the pancreas. Histologically, one case was a pleomorphic giant cell carcinoma consisting of pleomorphic giant/ small cells and spindle cells, one an osteoclast-like giant cell tumor composed of osteoclastoid giant cells and pleomorphic small cells, and one a pleomorphic giant cell carcinoma with osteoclastoid giant cells. Immunohistochemically, pleomorphic giant cells and small pleomorphic cells were positive for epithelial and mesenchymal markers throughout the cases. Osteoclastoid cells were strongly positive for PG-M1 (CD68), but negative for lysozyme and epithelial markers. Pleomorphic spindle cells showed the same immunoreactivity as pleomorphic giant/small cells. Genetically, all cases contained a mutation in the K-ras (codons 12, 13) oncogene, but neither p53 (exons 5-8) nor p16INK4 (exons 1, 2) gene mutations were found in any case. Furthermore, Loss of heterozygosity (LOH) of the p53, p161NK4. APC, and DPC4 gene loci was not found in any of the cases. Immunohistochemical study demonstrated this tumor to be of epithelial origin with mesenchymal differentiation. Genetically, initiation of the tumor is similar to that of usual ductal adenocarcinoma, but progression might be rather different. The peculiar histologic and biologic features of this tumor would be the result of changes in other functional genes.     

Loss of heterozygosity and analysis of mutation of p53 in hepatocellular carcinoma

Abstract Thirty-six hepatocellular carcinoma (HCC) tissues obtained from 34 patients were classified according to histological diagnosis into six well-differentiated HCC, 20 moderately differentiated HCC and 10 poorly differentiated HCC. High molecular weight DNA was prepared from each tumour and the corresponding non-tumour tissue. Loss of heterozygosity (LOH) on chromosomes 4q, 5q, 10q, 11p, 16q, 17p, mutation of the p53 gene and polymorphism of intron 25 of the retinoblastoma (RB) gene were simultaneously analysed. The patients were composed of three cases of small HCC (the diameter of which was < 3 cm) and 31 cases of advanced HCC. Twenty-nine of 34 (85.3%) patients analysed had been exposed to hepatitis B virus and/or hepatitis C virus. The frequencies of LOH on seven chromosomes were 57.9% in 17p13.3, 45.1% in 17p, 45.1% in 11p, 41.9% in 5q, 41.9% in 16q24, 29.0% in 4q, 25.8% in 10q in advanced HCC (four of well differentiated, 18 of moderately differentiated and nine of poorly differentiated carcinoma). In contrast, LOH was observed on 4q, 5q, 16q and 17p in 33% (1/3) of the small HCC (two of well differentiated and one of moderately differentiated carcinoma). The mutation of the p53 genes and polymorphism of the RB gene were present in 25.8% (8/31) and 12.9% (4/31) of the advanced tumours, respectively, but the mutation was not found in small HCC. LOH on every chromosome and the p53 mutation were observed more frequently in more advanced tumours, and the genetic changes accumulated with the increase of the histopathological grade. These findings suggest that the accumulation of genetic changes in multiple tumour suppressor genes is involved in the progression of HCC.     

Characterization of six tumor suppressor genes and microsatellite instability in hepatocellular carcinoma in southern African blacks

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Genetic analysis of p53 and RB1 tumor-suppressor genes in blast crisis of chronic myeloid leukemia

Summary We have investigated the involvement of the p53 and RB1 tumor-suppressor genes in 26 cases of chronic myeloid leukemia (CML) blast crisis, including 17 myeloid, eight lymphoid, and one megakaryoblastic crisis. The presence of p53 mutations in exons 5 through 9 was tested by the PCR-single-strand conformation polymorphism (SSCP) assay, followed by PCR-direct sequencing; in addition, loss of heterozygosity (LOH) at 17p13, the site of the p53 gene, was assayed by Southern blot. Given the variability of the mechanisms of inactivation of the RB1 gene in human tumors, a combination of Southern blot and mutational analysis by PCR-SSCP was used. p53 mutations were restricted to one case of myeloid blast crisis, showing a CGCTGC (ArgCys) mutation at codon 283; two additional cases displayed LOH at 17p13 in the absence of p53 mutations. No molecular lesions of the RB1 gene were detected in any of the cases analyzed. These data indicate that inactivation of p53 and RB1 is a rare event in the molecular pathogenesis of CML acute transformation.     

p53 gene mutations in gastric and esophageal cancers.

The presence of point mutation of the p53 gene in exons 5, 6, 7, and 8 was examined in 10 cases of gastric adenocarcinoma and 5 cases of esophageal squamous cell carcinoma by polymerase chain reaction and direct nucleotide sequencing. Mutations of the p53 gene were found in 5 cases of gastric cancer and 4 cases of esophageal cancer. The mutations in the stomach cancers consisted of four missence mutations (exons 5 and 8) and one frame shift (exon 7). In the esophageal cancers, three missence mutations (exons 6, 7, and 8) and one point mutation within the splice donor site of intron 5 were found. Of the seven missence mutations in the two cancers, five showed the transition from G to A and two from G to T. All these changes occurred in the highly conserved region of the p53 protein. These results suggest that mutations of the p53 gene are genetic events in the pathogenesis of gastric adenocarcinoma and esophageal squamous cell carcinoma.     

Mutations of p53 gene exons 4-8 in human esophageal cancer

AIM: To characterize the tumor suppressor gene p53 mutations in exon 4, esophageal cancer and adjacent non-cancerous tissues. METHODS: We performed p53 (exons 4-8) gene mutation analysis on 24 surgically resected human esophageal cancer specimens by PCR, single-strand conformation polymorphism, and DNA sequencing. RESULTS: p53 gene mutations were detected in 9 of 22 (40.9%) esophageal cancer specimens and 10 of 17 (58.8%) adjacent non-cancerous tissues. Eight of sixteen (50.0%) point mutations detected were G-A transitions and 9 of 18 (50.0%) p53 gene mutations occurred in exon 4 in esophageal cancer specimens. Only 1 of 11 mutations detected was G-A transition and 4 of 11 (36.4%) p53 gene mutations occurred in exon 4 in adjacent non-cancerous tissues. CONCLUSION: Mutation of p53 gene in exon 4 may play an important role in development of esophageal cancer. The observation of p53 gene mutation in adjacent non-cancerous tissues suggests that p53 gene mutation may be an early event in esophageal carcinogenesis. Some clinical factors, including age, sex, pre-operation therapy and location of tumors, do not influence p53 gene mutation rates.     

Evaluation of genetic mutations of tumor suppresser genes in colorectal cancer patients

BACKGROUND/AIMS: The mutation of tumor suppresser genes of colorectal cancer was evaluated to clarify its significance in the clinical management of colorectal cancer patients. METHODOLOGY: Polymerase chain reaction amplification was performed to investigate the loss of heterozygosity (LOH) of the DCC (deleted-in-colorectal-carcinoma) gene and p53 gene in 76 colorectal cancers. RESULTS: Thirty-five of 76 tumors showed LOH at the p53 locus. LOH at the DCC locus was observed in 30 of 76 tumors. Tumors with DCC LOH had a significantly higher rate of p53 LOH. DCC LOH was associated with both liver metastasis and lymph node metastasis. Moreover, younger patients and patients with a well-differentiated adenocarcinoma had a higher risk of liver and lymph node metastasis when the tumor had DCC LOH. The association between liver or lymph node metastasis and clinicopathological factors was stronger in tumors with smaller size and negative serosal invasion. CONCLUSIONS: The careful exploration of the liver and regional lymph nodes is advocated when the tumor has a DCC alteration, even at an early stage of the disease and especially in younger patients and patients with a well-differentiated carcinoma. The assessment of DCC LOH may be useful for selecting patients for extensive surgical intervention or adjuvant chemotherapy.     

Mutation of the p53 tumor suppressor gene in transitional cell carcinoma of the urinary tract in Taiwan

Early detection of a mutated p53 gene is thought to provide useful information in a wide range of human tumors. The aim of this study was to identify the role of the p53 gene in transitional cell carcinoma of the urinary tract. From March 1992 to July 2003, 75 patients (54 men and 21 women) with a mean age of 66.85 years and pathologically diagnosed transitional cell carcinoma were enrolled in this study. Fifty-eight patients had bladder cancer, eight had ureteral cancer, and nine had renal-pelvic cancer. Rapid screening for mutation of the p53 gene was performed using polymerase chain reaction (PCR), single-strand conformation polymorphism (SSCP), and sequencing analysis. Primer sets were designed to amplify fragments within exons 4, 5, 6, 7, and 8 of the p53 gene. Pathology classified 37 tumors as low grade and 38 as high grade. Tumor stage was pT1 or less in 29 patients and at least pT2 in 46 patients. Of the 75 patients in this study, 47 (62.7%) had a p53 mutation. Of the patients with a p53 mutation, 33 (70.2%) had invasive tumors. Invasive tumors were associated with p53 mutation (p < 0.05). Noted in 20 patients (26.7%), exon 4 was the most common site of the mutation. Of the patients with exon 4 mutations, 15 (75%) had invasive tumors and nine (45%) had high-grade tumors. Additionally, among the 20 patients with a common polymorphism at codon 72, 16 (80%) had invasive tumors and 14 (70%) had high-grade tumors. In this study, 62.7% of patients with transitional cell carcinoma had a p53 mutation, suggesting that the p53 gene mutation may be used as a marker of transitional cell carcinoma. Invasive tumors are more likely to have a p53 gene mutation. A simple analysis of the p53 gene using PCR/SSCP is suitable for screening for p53 abnormalities in transitional cell carcinoma. The relationship between cancer risk and the codon 72 polymorphism of exon 4 needs further investigation.     

Preliminary study on the loss of heterozygosity at 17p13 in gastric and colorectal cancers

AIM: To evaluate the role of p53 in the development and progression of colorectal cancer and gastric carcinoma by analyzing the loss of heterozygosity (LOH) at 17p13.1 and 17p13.3.METHODS: LOH at the p53 gene locus and 17p13.3 were examined in 22 cases of gastric carcinoma and 14 cases of colorectal cancer by Southern blot analysis.RESULTS: Of the 22 gastrocarcinoma cases, 12 (54%) were heterozygous and LOH was detected in 6 (50%) of the 12 informative cases. In the 14 colorectal cancer cases, 10 (71%) were heterozygous, and LOH was detected in 6 (60%) of the 10 informative cases.CONCLUSION: LOH at the p53 gene locus is a frequent event in multiple step carcinogenesis progression. The high frequency of LOH at 17p13.3 suggests that there may be another tumor suppresser gene in that chromosome region.     

Ki-ras codon 12 point mutation and p53 mutation in pancreatic diseases.

BACKGROUND/AIMS: The Ki-ras gene located at 12p, encodes the GTP binding protein involving the signal transduction system and concerns cell proliferation and differentiation. METHODOLOGY: Pancreatic tissues were obtained from 37 patients with various pancreatic diseases. Ki-ras codon 12 point mutation and p53 (exon 5-8) mutation were examined in 3 patients with chronic pancreatitis, 9 mucinous adenoma of the pancreas (2 with mucinous cystadenoma and 7 with intraductal papillary-mucinous adenoma), 22 pancreatic ductal carcinoma, and 3 serous cystadenoma. RESULTS: On usual pancreatic exocrine ductal lesions, Ki-ras point mutation was evident in 0% (0/3) of chronic pancreatitis, in 56% (5/9) of mucinous adenoma, and in 57% (12/21) of ductal carcinoma, the mutation being located in the second letter in 18 and in the 1st letter in 2. One Ki-ras codon 12 positive pancreatic cancer showed Ki-ras codon 12 point mutation in the surrounding pancreas (2nd letter mutation in both areas). p53 mutation was present in 0% (0/1) of chronic pancreatitis, in 0% (0/8) of mucinous adenoma, while it was evident in 29% (6/21) of pancreatic ductal carcinoma, the mutation being situated in exon 5 in 3, in exon 6 in 1, and in exon 7 in 2. In 3 patients with serous cystadenoma, there was no mutation in Ki-ras codon 12 or p53 (exon 5-8). CONCLUSIONS: These findings suggest that Ki-ras point mutation is involved in the early events of pancreatic ductal carcinoma, while p53 mutation is intricated in the late phase of pancreatic ductal carcinogenesis and the histogenesis of serous cystadenoma is different from that of pancreatic exocrine ductal lesions including mucinous adenoma and ductal carcinoma.     

p53 gene mutation in 150 dissected lymph nodes in a patient with esophageal cancer.

For thoracic esophageal cancer, we perform extended three field lymph node dissection, and have achieved nearly 50% of overall 5-year survival. However, patients sometimes develop lymph node recurrences in spite of having no lymph node metastases found by conventional histopathologic examination. In a patient with esophageal squamous cell carcinoma, we sequenced all the p53 cDNA translated regions (exon 2-10) of primary carcinoma, and confirmed one p53 nonsense mutation in exon 10. Then we extracted genomic DNA from 150 surgically dissected lymph nodes from that patient, and performed polymerase chain reaction analysis (PCR-RFLP) to detect the same p53 mutation in the lymph nodes. PCR-RFLP analysis showed the same p53 mutation in six lymph nodes. One node was located along the right recurrent laryngeal nerve, where no positive nodes was identified by conventional histopathologic examination. The p53 mutational diagnosis of metastatic cancer may be useful in detecting minimal residual disease.     

Loss of heterozygosity on chromosome 10q22-10q23 and 22q11.2-22q12.1 and p53 gene in primary hepatocellular carcinoma

AIM: To analyze loss of heterozygosity (LOH) and homozygous deletion on p53 gene (exon2-3, 4 and 11), chromosome 10q22-10q23 and 22q11.2 -22q12.1 in human hepatocellular carcinoma (HCC). METHODS: PCR and PCR-based microsatellite polymorphism analysis techniques were used. RESULTS: LOH was observed at D10S579 (10q22-10q23) in 4 of 20 tumors (20%), at D22S421 (22q11.2-22q12.1) in 3 of 20(15%), at TP53.A (p53 gene exon 2-3) in 4 of 20(20%), at TP53.B (p53 gene exon 4) in 6 of 20(30%), and at TP53.G (p53 gene exon 11) in 0 of 20(0%). Homozygous deletion was detected at 10q22-10q23(8/20; 40%), 22q11.2-22q12.1(8/20; 40%), p53 gene exon 2-3(0/20;0%), p53 gene exon 4(6/20; 30%), and p53 gene exon 11(2/20; 10%). CONCLUSION: There might be unidentified tumor suppressor genes on chromosome 10q22-10q23 and 22q11.2-22q12.1 that contribute to the pathogenesis and development of HCC.     

Codon 249 mutations of p53 gene in development of hepatocellular carcinoma

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p53基因在食管癌组织中的高表达

本文利用免疫组化LSAB法检测了p53基因在35例食管癌组织中的表达情况。35例食管癌标本中，60％（21／35）的标本癌组织都存在有p53基因的高表达，其中18例标本同时存在有癌旁粘膜上皮p53基因在10例癌旁粘膜上皮中也存在高表达。p53的高表达主要位于核内，部分也有胞浆表达。p53基因的高表达与癌组织的分化程度有关，分化越差，阳性率越高（P＜0．0025）。p53基因的表达存在异质性，并与肿瘤细胞的浸润转移及细胞周期的不同有关。我们的结果表明，p53基因的高表达在食管癌的发生中是一个常见的基因改变，它在食管癌的发生发展中起着重要的作用。     

Potential roles of tumor suppressor genes and microsatellite instability in hepatocellular carcinogenesis in southern African blacks

MAJOR POINTS OF THE COMMENTED ARTICLE Cumulative loss of heterozygosity (LOH) of chromosomal regions and tumor suppressor genes has been reported in hepatocellular carcinomas (HCCs) from China, Japan, and Korea. In this issue of the World Journal of Gastroenterology,Martins et al[1] report an analysis of LOH and microsatellite instability in HCCs from a group of 20 southern African blacks. Six known tumor suppressor genes-p53, RB1, BRCA1, BRCA2,WT1, and E-cadherin-were analyzed for LOH. In addition, the p53 gene was analyzed for the codon 249 mutation that is commonly found in subjects exposed to high levels of dietary aflatoxin B1.     

A study on p53 gene alterations in esophageal squamous cell carcinoma and their correlation to common dietary risk factors among population of the Kashmir valley

AIM: To systematically examine the extent of correlation of risk factors, such as age, consumed dietary habit and familial predisposition with somatic Tp53 molecular lesion causal to elevate carcinogenesis severity of esophageal squamous cell carcinoma (ESCC) among the Kashmiri population of Northern India. METHODS: All cases (n=51) and controls (n = 150) were permanent residents of the Kashmir valley. Genetic alterations were determined in exons 5-8 of Tp53 tumor suppressor gene among 45 ESCC cases histologically confirmed by PCR-SSCP analysis. Data for individual cancer cases (n = 45) and inpatient controls (n = 150) with non-cancer disease included information on family history of cancer, thirty prevailing common dietary risk factors along with patient's age group. Correlation of genetic lesion in p53 exons to animistic data from these parameters was generated by Chi-square test to all 45 histologically confirmed ESCC cases along with healthy controls. RESULTS: Thirty-five of 45 (77.8%) histologically characterized tumor samples had analogous somatic mutation as opposed to 1 of 45 normal sample obtained from adjacent region from the same patient showed germline mutation. The SSCP analysis demonstrated that most common p53 gene alterations were found in exon 6 (77.7%), that did not correlate with the age of the individual and clinicopathological parameters but showed significant concordance (P<0.05) with familial history of cancer (CD=58), suggesting germline predisposition at an unknown locus, and dietary habit of consuming locally grown Brassica vegetable "Hakh" (CD=19.5), red chillies (CD=20.2), hot salty soda tea (CD = 2.37) and local baked bread (CD=1.1). CONCLUSION: Our study suggests that somatic chromosomal mutations, especially in exon 6 of Tp53 gene, among esophageal cancer patients of an ethnically homogenous population of Kashmir valley are closely related to continued exposure to various common dietary risk factors, especially hot salty tea, meat, baked bread and "Hakh", that are rich in nitrosoamines and familial cancer history.     

Differential alterations of the genes in the CDKN2A-CCND1-CDK4-RB1 pathway are associated with the development of head and neck squamous cell carcinoma in Indian patients

Purpose The aim of this study was to analyse the alterations of the genes in the CDKN2A/CCND1/CDK4/RB1 pathway in the G1-S phase of the cell cycle during development of head and neck squamous cell carcinoma (HNSCC).Methods The alterations of these genes were analysed in 22 dysplastic lesions, 26 stage-I/II and 33 stage-III/IV HNSCC tumours of Indian patients.Results The alterations [mutation, hypermethylation, homozygous deletion and loss of heterozygosity/microsatellite size alteration (LOH/MA)] in the CDKN2A were found to be highest in 57% of the samples, followed by CCND1 amplification and LOH/MA at the RB1 locus in 14% and 8.5% of the samples, respectively. No dominant CDK4 Arg24Cys mutation was seen in our samples. Comparatively high frequency of CDKN2A alterations (except homozygous deletion) was found in dysplastic head and neck lesions and remained almost constant or increased during progression of the tumour, whereas the homozygous deletion of CDKN2A and the alterations in CCND1 and RB1 genes were seen mainly in the later stages of the tumour.Conclusions Our study suggested that mutation/hypermethylation/allelic alterations (LOH/MA) of CDKN2A were associated with the development of dysplastic head and neck lesions. All the other alterations might provide some cumulative effect during progression of later stages of the tumour to have selective growth advantages.