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1、Short CommunicationMolecular and Clinical Differences between Adenocarcinomas of the Esophagus and of the Gastric CardiaPhilippe Tanie `re,* Ghislaine Martel-Planche,* Daniela Maurici,* Catherine Lombard-Bohas,?Jean-Yves

2、 Scoazec,? Ruggero Montesano,* Franc ¸oise Berger,? and Pierre Hainaut*From the International Agency for Research on Cancer;* theFe ´de ´ration des Spe ´cialite ´s Digestives ? and the Laboratoir

3、ed’Anatomie Pathologique,? Ho ?pital Edouard Herriot,Lyon, FranceAdenocarcinoma of the esophagus (ADCE) with Bar- rett’s mucosa and adenocarcinoma of the cardia (ADCC) are often reported as a single pathological entity.

4、In this study we have used strict anatomical- pathological criteria to distinguish between these two lesions and we have investigated their differences in TP53 mutations, MDM2 gene amplification, and cyto- keratin expres

5、sion. DNA was extracted from the tu- mor areas of formalin-fixed, paraffin-embedded sec- tions in 26 ADCC and 28 ADCE patients. TP53 mutations were detected by temporal temperature gradient electrophoresis and identified

6、 by sequenc- ing. MDM2 amplification was assessed by differential polymerase chain reaction. The expression of cyto- keratins 4, 7, and 13 was examined by immunohisto- chemistry. In ADCC, the male to female ratio was 1.8

7、:1, compared to 27:1 in ADCE. Five ADCC patients had a history of other neoplasms, compared to only one ADCE patient. The two types of tumor differed in the prevalence of TP53 mutations (31% in ADCC and 50% in ADCE) and

8、of MDM2 gene amplification (19% in ADCC and 4% in ADCE), and in the pattern of expression of cytokeratin 7 (positive in 100% of ADCE and in 41% of ADCC) and cytokeratin 13 (positive in 81% of ADCE and in 36.5% of ADCC).

9、ADCE and ADCC differ in their clinical characteristics, in the preva- lence of TP53 mutations and MDM2 amplifications, and in the patterns of cytokeratin expression. These results support the notion that ADCC and ADCE ar

10、e distinct pathological entities. (Am J Pathol 2001, 158:33–40)Throughout the past 20 years, the incidence of tumors of the esophagogastric junction has increased at a rate of 5 to 10% per year in the United States and s

11、everal western European countries.1 The reasons for this increase are primarily unknown. Tumors of the esophagogastric junc- tion include two major types of adenocarcinoma: adeno- carcinomas of the esophagus (ADCE) and a

12、denocarci- nomas of the cardia (ADCC). ADCE occur in the distal part of the esophagus and develop from Barrett’s mucosa, a glandular metaplasia of the squamous epithelium that can vary in height from a few millimeters to

13、 a few centimeters. There is evidence that the metaplastic glandular cells are hybrid cells, ex- pressing cytokeratins (CKs) of both squamous (CK4 and 13) and glandular (CK8 and 19) origin2 and having ultra- structural f

14、eatures of both squamous and glandular cells.3 Furthermore, they have been shown to constantly express CK7, in contrast to intestinal metaplastic cells of the cardia mucosa, which never do.4 Barrett’s mucosa is often ass

15、ociated with chronic gastroesophageal acid re- flux. However, it can also occur in combination with chronic biliary alkaline reflux as well as in the absence of reflux.5 Factors predisposing to Barrett’s mucosa are not w

16、ell documented. Recent evidence suggests that ex- pression of certain polymorphic forms of glutathione-S- transferase P1 may be a genetic susceptibility factor for developing Barrett’s mucosa.6 Barrett’s mucosa is a very

17、 common lesion that is thought to occur in ?10% of the general population in the United States and is associated with a 10-fold increase in the risk of developing ADCE.7The cardia is the anatomical region corresponding t

18、o the transition between esophagus and stomach. It cannot be identified at the macroscopic level. At the microscopic level, the cardia is characterized by a thin mucosa with clear glandular cells, without any acid-secret

19、ing cells. It ranges in height from 1 to 5 mm, with an increase in size with age. The term “ADCC” applies to tumors locatedAccepted for publication September 14, 2000.Address reprint requests to P. Hainaut, Ph.D., Group

20、of MolecularCarcinogenesis, IARC, 150 Cours Albert Thomas, 69372 Lyon Cedex 08,France. E-mail: hainaut@iarc.fr.American Journal of Pathology, Vol. 158, No. 1, January 2001Copyright © American Society for Investigati

21、ve Pathology33antibody, clone AE1/AE3, 1/100; DAKO, Copenhagen, Denmark), and CK13 (monoclonal antibody, clone KS- 1A3, 1/50; Novocastra Laboratories Ltd.). Incubation with the relevant secondary antibodies (either anti-

22、mouse or an anti-rabbit biotinylated IgG, 1/200, Vectastain Elite- ABC kit; Vector Laboratories Inc.) for 30 minutes at room temperature was followed by streptavidin-peroxidase (1/ 50, 30 minutes at 37°C). Peroxidas

23、e activity was detected with a diaminobenzidine-based detection kit (Vector Lab- oratories, Inc.) and sections were counterstained with Mayer’s hematoxylin before dehydration and mounting.TP53 Mutation AnalysisTP53 exons

24、 4 to 9 were analyzed by temporal tempera- ture gradient electrophoresis using the DGene system (BioRad, Richmond, CA) and the primers described by Hamelin and colleagues20 (exons 5, 7, and 8) and Guldberg and colleagues

25、21 (exons 4, 6, and 9). DNA was amplified in a DNA thermocycler (Perkin Elmer, Norwalk, CT) in a 50-?l reaction mixture containing 5 ?l of genomic DNA, 20 pmol of sense and anti-sense primers, 200 ?mol/L of each dNTP, 1?

26、 amplification buffer, 1 X Q solution and 0.5 ?l (2.5 U) of Taq polymerase (HotStarTaq DNA polymerase; Qiagen, Hilden, Germany). Polymer- ase chain reaction (PCR) conditions were: 15 minutes at 95°C followed by 35 c

27、ycles at 95°C (1 minute), 56°C (exons 5 proximal, 8, and 9) or 62°C (exons 4a, 4b, 5 distal, 6, and 7) (1 minute), 72°C (90 seconds). The reaction was ended by a 10-minutes extension at 72°C. Het

28、eroduplex formation was induced by denaturation for 10 minutes at 98°C, followed by 30 minutes at the respec- tive annealing temperature (56°C or 62°C). Temporal temperature gradient electrophoresis was ru

29、n at 130V at temperatures optimized for each DNA fragment (exon 4p, 4d, 6, and 9: 58 to 70°C; exon 5p: 56 to 70°C; exon 5d: 63 to 70°C; exon 7: 59 to 70°C; exon 8: 53 to 67°C). A negative control

30、 (wild-type sample) and positive control (known mutant) were included in each analysis. Samples that showed additional and/or abnormal bands were re- amplified from genomic DNA and a second temporal temperature gradient

31、electrophoresis was performed. If confirmed, mutant alleles were cut from this second gel, re-amplified using the same primers, and analyzed by direct sequencing after asymmetric PCR amplifications as previously describe

32、d.20,22 Two cases with positive p53 immunostaining (?50%) did not show reproducible patterns of abnormal bands in temporal temperature gra- dient electrophoresis (case 12, Table 1, and case 3, Table 2). In these two case

33、s, mRNA was isolated from frozen biopsies, and cDNA was prepared and tested using the yeast functional assay as described by Flaman et al.23 Positive colonies were sequenced using the ABI PRISM 310 Genetic analyzer (Perk

34、in Elmer Biosystems, Foster City, CA).Analysis of MDM2 Gene AmplificationDifferential PCR was performed as previously de- scribed24 with the following modifications: 5 ?l of tem-plate DNA was amplified in 50 ?l of a reac

35、tion mixture containing 20 pmol each of sense and anti-sense primers for MDM2 and for the dopamine D2 receptor gene DRD2 (used as a reference), 200 ?mol/L of each dNTP, 1? amplification buffer, 1 X Q solution and 0.5 ?l

36、(2.5 U) of HotStarTaq DNA Polymerase (Qiagen). PCR conditions were: 15 minutes at 95°C, followed by 27 cycles at 95°C for 45 seconds, 55°C for 45 seconds, and 72°C for 1 minute with a final extension

37、at 72°C for 5 minutes. The primers were as follows: 5?-GAGGGCTTTGATGTTC- CTGA-3? (sense) and 5?-GCTACTAGAA GTTGATGGC-3? (anti-sense) for MDM2, and 5?-CCACTGAATCTGTCCT- GGTATG-3? (sense) and 5?-GTGTGGCATAGTAGTTG- TAG

38、TGG-3? (anti-sense) for human DRD2. PCR products were electrophoresed on 7.5% polyacrylamide gels stained with ethidium bromide, photographed, and the films were analyzed by scanning densitometry (GS-670; BioRad, Hercule

39、s, CA). An MDM2/DRD2 ratio of 2.5 or above was regarded as indicative of MDM2 amplification and a ratio between 2 and 2.5 was regarded as compat- ible with MDM2 amplification.Statistical EvaluationsFrequency tables of in

40、dependent variables were evaluated for statistical significance by Pearson’s chi-square test.ResultsClinical and Individual Characteristics of the PatientsTwenty-six cases of ADCC and 28 cases of ADCE were collected betw

41、een 1995 and 1999 (Tables 1 and 2). In one case, a tumor was classified as ADCE on the basis of the previous diagnosis on biopsy of a Barrett’s mucosa that was no longer detectable at surgery. None of the patients had re

42、ceived chemotherapy or radiotherapy be- fore biopsy or surgery. The mean age of patients was 62.1 ? 13.6 years (range, 25 to 82 years) for ADCC and 68.1 ? 9 years (range, 50 to 82 years) for ADCE. The group of ADCC patie

43、nts investigated included 17 men and nine women (male/female ratio of 0.65), whereas the ADCE patients were almost exclusively males (27 males and one female; male/female ratio 0.97). Despite the short follow-up pe- riod

44、 for some of the patients, medical records revealed that five of the ADCC patients had additional tumors. Three women developed a breast adenocarcinoma either before (19 years, patient 42; 2 years, patient 46) or after (

45、3 years, patient 33) diagnosis of ADCC. One of these patients (patient 46) also developed a malignant mela- noma 10 years before ADCC. One man (patient 38) had an adenocarcinoma of the intestine 10 years before ADCC and

46、another (patient 29) presented a pleomorphic adenoma of the parotid 5 years before ADCC. Among the ADCE patients, only one patient had a history of a previ- ous cancer (a squamous cell carcinoma of head and neck in a mal

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