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Biomedical subjects

R V Lord

Publications and source records attributed to R V Lord.

At least 19 recordsLinked to original sources
PubMed2003

Differential SPARC mRNA expression in Barrett's oesophagus.

Barrett's oesophagus (BE) is the precursor lesion to adenocarcinoma of the oesophagus. Understanding of the molecular alterations in this multistage process may contribute to improved diagnosis and treatment. Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein that modulates cell adhesion and growth. Alterations in SPARC expression have been observed in a variety of solid tumours. The aim of this study was to assess the prevalence and timing of SPARC mRNA expression in Barrett's multistage disease and to investigate the impact of SPARC alterations on the development and progression of this disease. SPARC mRNA expression was measured using a quantitative real-time RT-PCR method in 108 specimens from 19 patients with BE without carcinoma, 20 patients with Barrett's-associated adenocarcinoma (EA), and a control group (CG) of 10 patients without evidence of gastro-oesophageal reflux disease. The median SPARC mRNA expression was significantly upregulated in BE tissues compared to paired normal oesophagus (NE) tissues for the BE group (P=0.004) and for the EA group (P<0.001). The SPARC mRNA expression was significantly higher in adenocarcinoma of the oesophagus compared to matching NE tissue and compared to Barrett's tissues in the EA group (P<0.001). Furthermore, SPARC expression values were significantly different between metaplastic and dysplastic Barrett's tissues (P=0.014). In histologically normal squamous oesophagus tissues obtained from carcinoma patients (EA group), the SPARC mRNA expression was significantly higher compared to NE mucosa from the BE group and the CG group (P=0.03). These findings suggest that the upregulation of SPARC mRNA expression is an early event in the development and progression of BE and EA, and that high SPARC expression may be a clinically useful biomarker for the detection of occult adenocarcinoma, and that a widespread 'field effect' is present in the NE of patients with oesophageal adenocarcinoma.

Adenocarcinoma↗
PubMed2001

Adenomatous polyposis coli gene promoter hypermethylation in non-small cell lung cancer is associated with survival.

Methylation of 5' CpG islands in promoter and upstream coding regions has been identified as a mechanism for transcriptional inactivation of tumor suppressor genes. The purpose of this study was to determine whether hypermethylation of the adenomatous polyposis coli (APC) gene promoter occurs in primary non-small cell lung cancer (NSCLC), and whether hypermethylated APC has any relationship with survival. APC promoter 1A methylation was determined in normal and corresponding tumor tissue from 91 NSCLC patients and in a control group of 10 patients without cancer, using a quantitative fluorogenic real-time PCR (Taqman) system. APC promoter methylation was detectable in 86 (95%) of 91 tumor samples, but also in 80 (88%) of 91 normal samples of NSCLC patients, and in only two (20%) of 10 normal lung tissues of the control group. The median level of APC promoter methylation was 4.75 in tumor compared to 1.57 in normal lung tissue (P<0.001). Patients with low methylation status showed significantly longer survival than did patients with high methylation status (P=0.041). In a multivariate analysis of prognostic factors, APC methylation was a significant independent prognostic factor (P=0.044), as were pT (P=0.050) and pN (P<0.001) classifications. This investigation shows that APC gene promoter methylation occurs in the majority of primary NSCLCs. High APC promoter methylation is significantly associated with inferior survival, showing promise as a biomarker of biologically aggressive disease in NSCLC.

Adenocarcinoma↗
PubMed2001

Risk factors and the prevalence of trocar site herniation after laparoscopic fundoplication.

BACKGROUND: Although there have been case reports describing trocar site herniation after laparoscopic fundoplication, its overall prevalence and the risk factors for its development are unclear. METHODS: The records of 320 patients undergoing primary laparoscopic fundoplication as treatment for gastroesophageal reflex disease (GERD) or hiatal hernia between 1991 and 1999 were reviewed retrospectively. Placement of the initial supraumbilical trocar was by the open Hassan technique in all patients. RESULTS: Nine patients (five male) with a mean age 54 years (range, 37-75) developed trocar site herniation, for an overall prevalence of 3%. The mean interval between surgery and diagnosis was 12 months (range, 4-21). In all patients, the hernia occurred at the supraumbilical camera port site. Patients with trocar hernias tended to have a higher body mass index (BMI) than those without hernias (mean BMI, 29.4 kg/m2 vs 27.2 kg/m2, p = 0.13). None of the patients developed intestinal obstruction as a consequence of herniation. To date, all but one of the hernias have been repaired. Six of them required the insertion of a prosthetic mesh. CONCLUSIONS: The prevalence of trocar site herniation after laparoscopic fundoplication was minimal at 3%. All hernias occurred at the midline supraumbilical port, the only site where open trocar insertion was employed. As a consequence of these observations, we have developed a new method of open trocar placement. This method utilizes a paramedian skin incision and separate fascial incisions through anterior and posterior rectus sheathes, with retraction of the rectus abdominis muscle laterally.

Abdomen↗
PubMed2001

Epigenetic patterns in the progression of esophageal adenocarcinoma.

Esophageal adenocarcinoma (EAC) arises after normal squamous mucosa undergoes metaplasia to specialized columnar epithelium (intestinal metaplasia or Barrett's esophagus), which can then ultimately progress to dysplasia and subsequent malignancy. Epigenetic studies of this model have thus far been limited to the DNA methylation analysis of a few genes. In this study, we analyzed a panel of 20 genes using a quantitative, high-throughput methylation assay, METHYLIGHT: We used this broader approach to gain insight into concordant methylation behavior between genes and to generate epigenomic fingerprints for the different histological stages of EAC. Our study included a total of 104 tissue specimens from 51 patients with different stages of Barrett's esophagus and/or associated adenocarcinoma. We screened 84 of these samples with the full panel of 20 genes and found distinct classes of methylation patterns in the different types of tissue. The most informative genes were those with an intermediate frequency of significant hypermethylation [ranging from 15% (CDKN2A) to 60% (MGMT) of the samples]. This group could be further subdivided into three classes, according to the absence (CDKN2A, ESR1, and MYOD1) or presence (CALCA, MGMT, and TIMP3) of methylation in normal esophageal mucosa and stomach, or the infrequent methylation of normal esophageal mucosa accompanied by methylation in all normal stomach samples (APC). The other genes were less informative, because the frequency of hypermethylation was below 5% (ARF, CDH1, CDKN2B, GSTP1, MLH1, PTGS2, and THBS1), completely absent (CTNNB1, RB1, TGFBR2, and TYMS1), or ubiquitous (HIC1 and MTHFR), regardless of tissue type. Each class undergoes unique epigenetic changes at different steps of disease progression of EAC, suggesting a step-wise loss of multiple protective barriers against CpG island hypermethylation. The aberrant hypermethylation occurs at many different loci in the same tissues, suggestive of an overall deregulation of methylation control in EAC tumorigenesis. However, we did not find evidence for a distinct group of tumors with a CpG island methylator phenotype. Finally, we found that normal and metaplastic tissues from patients with evidence of associated dysplasia or cancer had a significantly higher incidence of hypermethylation than similar tissues from patients with no further progression of their disease. The fact that the samples from these two groups of patients were histologically indistinguishable, yet molecularly distinct, suggests that the occurrence of such hypermethylation may provide a clinical tool to identify patients with premalignant Barrett's who are at risk for further progression.

Adenocarcinoma↗
PubMed2001

Predictors of response after laparoscopic splenectomy for immune thrombocytopenic purpura.

BACKGROUND: Splenectomy has been shown to produce long term remission in patients with immune thrombocytopenic purpura (ITP). With the development of laparoscopic splenectomy, there is renewed interest in the surgical treatment of ITP. The aim of this study was to identify factors that are predictive of outcome after laparoscopic splenectomy for ITP. METHODS: A case series of 67 consecutive patients with ITP undergoing laparoscopic splenectomy was reviewed. A positive response was defined as a postoperative platelet count greater than 150,000/ml requiring no maintenance medical therapy on follow-up evaluation. A chi-square test and a stepwise logistic regression analysis were performed for the following variables: age, gender, preoperative response to steroids, duration of disease, severity of preoperative bleeding, accessory spleens, and thrombocytosis on discharge. RESULTS: At a median follow-up period of 38 months (range, 2-56 months), 52 patients (78%) had a positive response to laparoscopic splenectomy. Of the 15 patients (22%) who did not have a positive response, 11 were refractory and 4 relapsed. All relapses occurred in patients with a platelet count less than 150,000/microl at discharge. Patient age was the most significant predictive factor for success or failure of the operation. The median age of the responders (31 years; range, 19-71 years) was significantly lower than the median age of the nonresponders (49 years; range, 24-62; p < 0.001). Only 5.6% of those younger than 40 years did not have a positive response, compared with 42% of patients older than 40 years (p < 0.05). Patient age was significantly associated with outcome on univariable chi-square analysis (p = 0.001), and was the only significant factor on multivariable analysis (odds ratio, 2.65; 95% confidence interval, 1.71-4.1). Other significant predictors of outcome on univariable analysis were preoperative response to corticosteroids and platelet count on discharge. CONCLUSIONS: A long-lasting response after splenectomy for ITP is more likely to occur in patients younger than 40 years of age. To avoid the long-term side effects of corticosteroid use, early surgical referral of younger patients with ITP should be considered.

Adult↗
PubMed2001

Increased c-myb mRNA expression in Barrett's esophagus and Barrett's-associated adenocarcinoma.

BACKGROUND: Esophageal adenocarcinoma develops through a multistage process which is characterized histopathologically by progression from Barrett's intestinal metaplasia to Barrett's esophagus with dysplasia and ultimately to adenocarcinoma. The genetic basis of this process is increasingly well understood, but no studies have examined the role of the transcription factor c-myb in this disease. MATERIALS AND METHODS: c-myb mRNA expression levels were measured using a quantitative reverse transcription-polymerase chain reaction (RT-PCR) method in specimens of Barrett's intestinal metaplasia (n = 16), adenocarcinoma (n = 22), matching normal squamous esophagus tissues (n = 38), and normal squamous esophagus tissues from patients without Barrett's esophagus or chronic gastroesophageal reflux disease (n = 10). RESULTS: The median c-myb mRNA expression levels were significantly increased in Barrett's intestinal metaplasia tissues compared to normal esophagus tissues (P = 0.013) and in Barrett's-associated adenocarcinoma tissues compared to normal squamous esophagus tissues (P = 0.001). The c-myb expression levels increased progressively and significantly in histopathologically worse tissue types, with an increase from normal squamous esophagus mucosa to Barrett's intestinal metaplasia, and from Barrett's intestinal metaplasia to adenocarcinoma of the esophagus (P = 0.002). Median c-myb expression levels were also significantly higher in histologically normal squamous esophagus tissues from cancer patients compared to normal esophagus tissues from patients without cancer (P < 0.001) and a control group without evidence of Barrett's esophagus or gastroesophageal reflux disease (P = 0.003). Very high c-myb mRNA expression levels were found only in patients with cancer. CONCLUSION: These findings suggest that upregulation of c-myb mRNA expression is an early event in the development of Barrett's esophagus and associated adenocarcinoma, that high c-myb mRNA expression levels may be a clinically useful biomarker for the detection of occult adenocarcinoma, and that a widespread cancer "field" effect is present in the esophagus of patients with Barrett's-associated adenocarcinoma.

Adenocarcinoma↗
PubMed2001

Retinoic acid receptor-alpha messenger RNA expression is increased and retinoic acid receptor-gamma expression is decreased in Barrett's intestinal metaplasia, dysplasia, adenocarcinoma sequence.

BACKGROUND: Expression levels of the retinoic acid receptors (RAR-alpha, RAR-beta, and RAR-gamma) are significantly different in neoplastic tissues compared with non-neoplastic tissues for some tumors. This study investigated whether retinoic acid receptor messenger RNA (mRNA) expression levels are altered in Barrett's esophagus and Barrett's adenocarcinoma tissues. METHODS: Relative mRNA expression levels of the RARs were quantified by using the ABI 7700 Sequence Detector (Taqman) system in Barrett's intestinal metaplasia (n = 15), dysplasia (n = 6), adenocarcinoma (n = 17), and matching normal esophagus tissues (n = 36). RESULTS: RAR-alpha expression was significantly increased, and RAR-gamma expression was significantly decreased, at higher stages in the Barrett's sequence. There was almost complete loss of RAR-gamma expression (relative expression level < or = 1) in a majority (70%) of the dysplasia and adenocarcinoma tissues. There were significant differences in RAR-alpha and RAR-gamma expression in histopathologically normal tissues in patients with cancer versus patients without cancer. RAR-beta expression levels were significantly elevated in adenocarcinoma versus normal esophagus tissues. The RAR expression profile was similar for cancers arising within the esophagus and for cancers arising at the gastroesophageal junction. CONCLUSIONS: RAR mRNA expression levels are significantly different in Barrett's tissues compared with normal esophagus tissues, and these levels are significantly different in Barrett's dysplasia and adenocarcinoma tissues compared with nondysplastic tissues. These results suggest that RAR mRNA levels may be useful biomarkers for this disease and that gastroesophageal junction adenocarcinomas are genetically similar to esophageal adenocarcinomas. These results also suggest that a cancer field is present in the esophagus in patients with cancer and that genetic alterations can precede histopathologic alterations in this disease.

Adenocarcinoma↗
PubMed2001

Carditis: a manifestation of gastroesophageal reflux disease.

This series consists of 141 patients in whom cardiac mucosa (CM) was present in biopsy samples from the gastroesophageal junctional region. Inflammation of CM, irrespective of its exact anatomic location, was defined as carditis and classified as acute or chronic based on the number of inflammatory cells present. In all cases, CM showed significant chronic inflammation. One hundred and eleven (79%) of the 141 patients with carditis showed no evidence of gastritis in biopsy samples from the gastric antrum and body. Helicobacter pylori was present in 20 of 141 (14%) patients; of these, 17 had evidence of a pangastritis, with 15 of these patients also showing H. pylori in CM. Patients with severe chronic inflammation in CM had a significantly higher acid exposure of the lower esophagus as quantitated by a 24-hour pH test than those with mild chronic inflammation in CM. Acute inflammation was uncommon in CM; it was present in only 26 of 141 (18.4%) patients. There was no significant difference in acid exposure of the lower esophagus between patients with and without acute inflammation in CM. The presence of acute inflammation in CM was significantly associated with distal gastritis and H. pylori infection. Men with carditis had quantitatively higher acid exposure of the lower esophagus than did women with this disorder. This difference was greatest in men with severe inflammation in CM who had no evidence of distal gastritis. These findings provide evidence that chronic inflammation in CM is strongly associated with acid reflux and that H. pylori is not a significant etiologic factor in carditis. They also show that in patients with CM in whom H. pylori gastritis develops, the infection frequently spreads to involve CM, resulting in acute inflammation with neutrophils that is superimposed on the chronic inflammation already present.

Adolescent↗
PubMed2000

Hypermethylated APC DNA in plasma and prognosis of patients with esophageal adenocarcinoma.

BACKGROUND: The adenomatous polyposis coli (APC) locus on chromosome 5q21-22 shows frequent loss of heterozygosity (LOH) in esophageal carcinomas. However, the prevalence of truncating mutations in the APC gene in esophageal carcinomas is low. Because hypermethylation of promoter regions is known to affect several other tumor suppressor genes, we investigated whether the APC promoter region is hypermethylated in esophageal cancer patients and whether this abnormality could serve as a prognostic plasma biomarker. METHODS: We assayed DNA from tumor tissue and matched plasma from esophageal cancer patients for hypermethylation of the promoter region of the APC gene. We used the maximal chi-square statistic to identify a discriminatory cutoff value for hypermethylated APC DNA levels in plasma and used bootstrap-like simulations to determine the P: value to test for the strength of this association. This cutoff value was used to generate Kaplan-Meier survival curves. All P values were based on two-sided tests. RESULTS: Hypermethylation of the promoter region of the APC gene occurred in abnormal esophageal tissue in 48 (92%) of 52 patients with esophageal adenocarcinoma, in 16 (50%) of 32 patients with esophageal squamous cell carcinoma, and in 17 (39.5%) of 43 patients with Barrett's metaplasia but not in matching normal esophageal tissues. Hypermethylated APC DNA was observed in the plasma of 13 (25%) of 52 adenocarcinoma patients and in two (6.3%) of 32 squamous carcinoma patients. High plasma levels of methylated APC DNA were statistically significantly associated with reduced patient survival (P =.016). CONCLUSION: The APC promoter region was hypermethylated in tumors of the majority of patients with primary esophageal adenocarcinomas. Levels of hypermethylated APC gene DNA in the plasma may be a useful biomarker of biologically aggressive disease in esophageal adenocarcinoma patients and should be evaluated as a potential biomarker in additional tumor types.

Adenocarcinoma↗
PubMed2000

Fields of aberrant CpG island hypermethylation in Barrett's esophagus and associated adenocarcinoma.

Esophageal adenocarcinoma (EAC) is thought to develop through a multistage process in which Barrett's metaplasia progresses through low- and high-grade dysplasia to invasive cancer. Transcriptional silencing of tumor suppressor genes by promoter CpG island hypermethylation has been observed in many types of human cancer. Analysis of CpG island hypermethylation in EAC has thus far been limited to the CDKN2A (p16) gene. In this study, we extend the methylation analysis of EAC to include three other genes, APC, CDH1 (E-cadherin), and ESR1 (ER, estrogen receptor alpha), in addition to CDKN2A. Molecular analysis can provide insight into the complex relationships between tissues with different histologies in Barrett's esophagus and associated adenocarcinoma. Therefore, we have mapped the spatial distribution of methylation patterns in six esophagectomy cases in detail. Hypermethylation of the four CpG islands was analyzed by the MethyLight technique in 107 biopsies derived from these six patients for a total of 428 methylation analyses. Our results show that normal esophageal squamous epithelium is unmethylated at all four CpG islands. CDH1 is unmethylated in most other tissue types as well. Hypermethylation of ESR1 is seen at high frequency in inflammatory reflux esophagitis and at all subsequent stages, whereas APC and CDKN2A hypermethylation is found in Barrett's metaplasia, dysplasia, and EAC. When it occurs, hypermethylation of APC, CDKN2A, and ESR1 is usually found in a large contiguous field, suggesting either a concerted methylation change associated with metaplasia or a clonal expansion of cells with abnormal hypermethylation.

Adenocarcinoma↗
PubMed2000

Is adenocarcinoma following esophagoduodenostomy without carcinogen in the rat reflux-induced?

BACKGROUND: A widely used rat model for reflux-induced esophageal adenocarcinoma in the absence of carcinogens involves induction of duodenoesophageal reflux by performance of esophagoduodenostomy. The aim of this study was to test the hypothesis that acid reflux reduces the incidence of adenocarcinoma in this animal model. METHODS: One hundred ninety 8-week-old male Sprague-Dawley rats were studied. The animals were randomly divided into four groups with a different type of reflux established in each group. Group 1 had an esophagoduodenostomy for duodenogastroesophageal reflux (n = 59), group 2 had an esophagoduodenostomy and a total gastrectomy for duodenoesophageal reflux (n = 54), group 3 had an esophagoduodenostomy and a total gastrectomy with acid supplementation with acidified water to control for the effect of the gastrectomy (n = 50), and group 4 had a total gastrectomy with Roux-en-Y reconstruction to eliminate all reflux (n = 25). One hundred eighty-eight surviving animals were sacrificed at 36 weeks of age and the resected esophagi were examined. RESULTS: All animals except the no reflux control group had severe reflux esophagitis. The frequency of tumor development was similar in all study groups. All of the tumors were well-differentiated adenocarcinomas that were located on the external surface of the bowel either at or immediately distal to the esophagoenteric anastomosis. The tumors appeared to arise from the submucosa and did not involve the overlying mucosa. There was no definite evidence of columnar lining of the esophagus but an admixture of squamous and columnar epithelium was found microscopically in all groups. This finding was unrelated to the presence and composition of reflux. CONCLUSIONS: Adenocarcinomas in this animal model are not reflux-induced and do not arise from the mucosa. Despite previous reports to the contrary, we suggest that this model may not be valid for the study of reflux-induced esophageal adenocarcinoma.

Adenocarcinoma, Mucinous↗
PubMed2000

Determinants of intestinal metaplasia within the columnar-lined esophagus.

HYPOTHESIS: The clinical and physiological features of patients with short segments of columnar-lined esophagus (CLE) with and without intestinal metaplasia (IM) are distinct. DESIGN: Retrospective case series. SETTING: University tertiary referral center. PATIENTS: Sixty-five consecutive patients with a 2-cm or shorter length of endoscopically visible CLE. INTERVENTIONS: The type of CLE and the presence of Helicobacter pylori were determined by histopathologic examination of esophageal and gastric antrum biopsy specimens. All patients underwent esophageal manometry and simultaneous 24-hour pH and bilirubin monitoring. MAIN OUTCOME MEASURES: Clinical and physiological data were compared in patients with and without IM. RESULTS: Thirty-six patients had IM and 29 had cardiac-type mucosa without IM in biopsy specimens from the CLE. There was no significant difference in age or sex distribution, but the duration of symptoms was significantly longer in patients with IM (10 vs 5 years; P = .03). Abnormal esophageal acid exposure was found in 30 (83%) of 36 patients with IM and 23 (79%) of 29 patients without IM. The prevalence of abnormal bilirubin exposure was significantly higher in patients with IM (75% [27/36]) than in those without IM (41% [12/29]; P = .01). There was no significant difference in the prevalence of H pylori infection between the 2 groups (8% vs 10%; P >.99). CONCLUSIONS: Patients with short segments of CLE and IM have similar esophageal acid exposure but significantly higher frequency of abnormal bilirubin exposure and longer median duration of reflux symptoms than patients without IM. Therefore, CLE, regardless of histological type, is a manifestation of gastroesophageal reflux disease. The presence of duodenoesophageal reflux and the duration of reflux seem to be important in the pathogenesis of IM.

Barrett Esophagus↗
PubMed2000

Prevalence of Helicobacter pylori infection in 160 patients with Barrett's oesophagus or Barrett's adenocarcinoma.

BACKGROUND: The role of Helicobacter pylori infection in the development of Barrett's oesophagus and its complications is uncertain. The aim of the present study was to determine the importance of H. pylori infection in this disease by comparing the frequency of oesophageal and gastric H. pylori infection in a group of patients with Barrett's oesophagus or adenocarcinoma, with the frequency of infection in a control group without Barrett's disease. METHODS: The study group included 160 patients (123 male, 37 female; mean age: 61.2 years) who were classified (according to the highest grade pathological lesion in the oesophagus) as having Barrett's intestinal metaplasia (IM; 88 patients), Barrett's oesophagus with low-grade dysplasia (LGD; 28 patients), high-grade dysplasia (HGD; five patients), Barrett's indefinite for dysplasia (n = 4), and Barrett's adenocarcinoma (33 patients). A total of 91 of these patients had gastric antral specimens available for study. The control group consisted of 214 consecutive, prospectively enrolled symptomatic patients (122 male, 92 female; mean age: 57.2 years) who underwent upper gastrointestinal endoscopy and in whom Barrett's oesophagus or Barrett's adenocarcinoma was not found. A modified Warthin-Starry method was used to detect H. pylori infection. RESULTS: Oesophageal H. pylori infection was found in eight of 160 (5%) patients with Barrett's oesophagus or Barrett's adenocarcinoma. Holicobacter pylori organisms in the oesophagus were found only on non-intestinalized cardiac or oxyntocardiac mucosa. All patients with oesophageal H. pylori infection and an antral biopsy available for study had antral H. pylori infection. Gastric antral H. pylori infection was significantly less prevalent in patients in the Barrett's study group (15/91, 16.5%) than in the non-Barrett's control group (67/214, 31.3%; Fisher's exact test, P = 0.01). Patients from the control group with an endoscopic diagnosis of duodenal ulcer, gastric ulcer, gastritis, or duodenitis had a significantly higher prevalence of infection compared with the Barrett's group, but there was no difference in the infection prevalence in patients in the Barrett's group and patients with reflux oesophagitis, hiatal hernia, no endoscopic abnormality, or any other diagnosis. CONCLUSIONS: Oesophageal H. pylori infection is uncommon in patients with Barrett's IM, dysplasia, or adenocarcinoma, and may be restricted to non-intestinalized columnar epithelium. Gastric H. pylori infection may have a protective effect for the development of Barrett's oesophagus.

Adenocarcinoma↗
PubMed2000

K-ras codon 12 mutations in Barrett's oesophagus and adenocarcinomas of the oesophagus and oesophagogastric junction.

BACKGROUND: Activation of the ras oncogene is commonly found in gastrointestinal tract cancers, but the role of ras in the development and progression of Barrett's oesophagus and associated cancers is uncertain. METHODS: The frequency of K-ras codon 12 point mutations was assessed in 52 paraffin-embedded tissues from 44 patients with oesophageal pathology. The specimens were classified pathologically as follows: adenocarcinoma of the oesophagus or oesophagogastric junction (n = 23), Barrett's high-grade dysplasia (n = 5), low-grade dysplasia (n = 14), intestinal metaplasia (n = 4), normal oesophagus (n = 5) or normal stomach (n = 1). DNA was extracted from three consecutive sections of each paraffin block and mutations at bases 1 and 2 of K-ras codon 12 were identified using a novel restriction endonuclease-mediated selective polymerase chain reaction method. RESULTS: Mutations were found in 7 of 23 (30.4%) adenocarcinomas and in 2 of 5 (40%) high-grade dysplasia specimens. No mutations were found in specimens of low-grade dysplasia, intestinal metaplasia without dysplasia, or normal oesophagus and stomach. There were no significant associations between the presence of mutations and clinicopathologic features in the patients with cancer. One patient who progressed from low-grade to high-grade dysplasia was found to have developed mutant K-ras in the course of this transformation. CONCLUSION: These results suggest that K-ras codon 12 mutations may occur frequently in patients with Barrett's oesophagus with high-grade dysplasia or adenocarcinoma of the oesophagus or oesophagogastric junction. K-ras mutation may be a late event in the Barrett's metaplasia-dysplasia-adenocarcinoma sequence.

Adenocarcinoma↗