The molecular biology of esophageal carcinoma

Durable and Complete Response to Herceptin Monotherapy in Patients with Metastatic Gastroesophageal Cancer

Gastroesophageal cancer is the sixth leading cause of cancer-related death worldwide. The 2 most common histologies are squamous cell carcinoma and adenocarcinoma, which has seen an increase in incidence correlating with an increase in obesity in developed countries. Gastroesophageal adenocarcinoma has a preponderance to metastasize early, making it a highly lethal cancer with a low 5-year survival rate of ∼15-25%. Therefore, for the majority of patients, treatment focuses on palliation and prolongation of survival. Combination chemotherapy regimens, mostly platinum-based, have only modestly prolonged survival in patients with stage IV disease. Recently, it was discovered that the activation of the HER2 receptor plays an important role in a minority of adenocarcinomas of the distal esophagus and stomach. This introduced the treatment option of trastuzumab (Herceptin), a monoclonal antibody directed at the HER2 receptor, which has demonstrated improvement in overall and progression-free survival as noted in the ToGA trial. Currently, the role of Herceptin therapy beyond first-line therapy and outside of combination regimens is not well established. In this case report we review 2 cases of patients with gastroesophageal cancer, with HER2 overexpression, who achieved a robust response to trastuzumab in combination with chemotherapy and were able to maintain a durable response with maintenance trastuzumab monotherapy.

CDK/CCN and CDKI alterations for cancer prognosis and therapeutic predictivity

The regulation of cell growth and division occurs in an accurate sequential manner. It is dictated by the accumulation of cyclins (CCNs) and cyclin-dependent kinases (CDKs) complexes and degradation of CCNs. In human tumors, instead, the cell cycle is deregulated, causing absence of differentiation and aberrant cell growth. Oncogenic alterations of CCNs, CDKs, and CDKIs have been reported in more than 90% of human cancers, and the most frequent are those related to the G1 phase. Several molecular mechanisms, including gene overexpression, chromosomal translocations, point mutations, insertions and deletions, missense and frame shift mutation, splicing, or methylation, may be responsible for these alterations. The cell cycle regulators are involved in tumor progression given their association with cancers characterized by higher incidence of relapses and chemotherapy resistance. In the last decade anticancer drug researches focused on new compounds, able to target molecules related to changes in genes associated with tumor status. Recently, the studies have focused on the restoration of cell cycle control modulating molecular targets involved in cancer-cell alterations. This paper aims to correlate alterations of cell cycle regulators with human cancers and therapeutic responsivity.

The influence of high body mass index on the prognosis of patients with esophageal cancer after surgery as primary therapy

BACKGROUND

High body mass index (BMI), a prevalent condition in the United States, is associated with esophageal adenocarcinoma (EAC). Its influence on a patient's outcome remains unclear. In the current study, the authors examined the impact of BMI on survival and complications in patients with esophageal cancer (EC) who underwent surgery as their primary therapy.

METHODS

The authors retrospectively reviewed 301 consecutive EC patients who underwent surgery but received no adjunctive therapy. Patients were segregated into 2 subgroups based on their baseline BMI: normal/low (<25 kg/m(2) ) and high (≥25 kg/m(2) ).

RESULTS

Seventy-six (25%) patients had a BMI <25 kg/m(2) and 225 (75%) patients had a BMI ≥25 kg/m(2) . In the high BMI group, there were more men (P < .001), fewer upper ECs (P = .021), a lower baseline clinical stage (P = .006), and frequent EAC (P < .001). Postoperative morbidity was similar in both groups, with the exception of gastrointestinal complications (P = .016). The 5-year overall survival (OS) rates were 44% in the normal/low BMI group and 60% in the high BMI group (P = .017). The 5-year disease-free survival (DFS) rates were 41% in the normal/low BMI group and 60% in the high BMI group (P = .005). On multivariable analysis, age, weight loss, peripheral vascular disease (PVD), and both clinical and pathological stage of disease were found to be independent prognosticators for OS. Older age (hazard ratio [HR], 1.029; 95% confidence interval [95% CI], 1.009-1.049 [P = .004]), weight loss (HR, 1.525; 95% CI, 1.034-2.248 [P = .033]), and PVD (HR, 2.325; 95% CI, 1.039-5.204 [P = .040]) were found to be associated with poor OS.

CONCLUSIONS

High BMI is common in EC patients and the better OS/DFS noted in patients with a high BMI is because of the diagnosis of a low baseline clinical stage. Confirmation of these findings is warranted.

Gli-1 expression is associated with lymph node metastasis and tumor progression in esophageal squamous cell carcinoma

OBJECTIVE

We investigated the expression and function of the hedgehog (Hh) pathway in human esophageal squamous cell carcinoma (ESCC).

METHODS

The expression of Hh pathway molecules were detected in 34 human ESCC cell lines by RT-PCR. Subsequently, we investigated the effects of cyclopamine, a specific inhibitor of the Hh pathway, on cell proliferation, migration and invasion. Next, the effects of siRNA targeting Gli-1 were examined. Immunohistochemically, the expression of Gli-1 was studied in 104 ESCC specimens and compared with the clinicopathological characteristics of the patients.

RESULTS

Gli-1 were expressed in 31 of 34 cell lines (91%), while Sonic hedgehog (SHh), Patched (Ptch), and Smoothened (Smo) expression was noted in all 34 cell lines. Cyclopamine significantly inhibited cell proliferation and migration in ESCC cells that expressed Gli-1. siRNA targeting Gli-1 inhibited cell growth in ESCC cells. Gli-1 was expressed in 52 of 104 cancer specimens (50%). Gli-1 expression was associated with tumor depth (p < 0.001), positive lymph node metastasis (p = 0.004) and a poor prognosis (p = 0.0047).

CONCLUSION

Our results raise the possibility that the inhibition of the Hh pathway could be a novel target for esophageal cancer therapy.

Barrett's esophagus: model of neoplastic progression

Human cancer progression is characterized by clonal expansion of cells with accumulated genetic errors. Invasive carcinomas contain all the genetic errors that were acquired during neoplastic progression and then continue to accumulate further abnormalities, leading to tumor heterogeneity. Many investigations of human cancer have given valuable insights in genetic abnormalities important for tumor biology. Early events responsible for neoplastic progression, however, are often impossible to investigate in invasive cancers because the premalignant tissue in which the tumors develop are often overgrown and the premalignant conditions cannot be studied in vivo because they are either not detected owing to lack of symptoms or are removed before cancer develops. Unlike many other premalignant conditions Barrett's esophagus is often associated with symptoms leading to diagnosis at an early stage before cancer develops, and the premalignant epithelium is seldom removed at an early stage of cancer progression. Furthermore, in patients who present with invasive carcinoma the tumor is often surrounded by premalignant epithelium, which is available for further investigations. Therefore Barrett's esophagus is an excellent model in which to study the early events of neoplastic progression. It may not only contribute to a better understanding of the neoplastic process but also provide a base for safer assessment of cancer risk during surveillance for early detection of esophageal adenocarcinoma.

Molecular markers and staging of early esophageal cancer

BACKGROUND

Patients with early esophageal cancer experience varying clinical outcomes despite identical tumor staging by standard diagnostic methods because clinical and histopathological staging fail to reveal the underlying complex biology of cancer.

METHODS AND FOCUS

This review discusses some of the current concepts of molecular staging with the potential to enhance the current staging methods of patients with early esophageal cancer.

CONCLUSIONS

Understanding the molecular biology of esophageal cancer has increased substantially, and clinicians anticipate the translation of the gained knowledge into patient care. Numerous molecular techniques are potentially available for analyzing biological aspects of the individual tumor for improved staging.

HPV infections and oesophageal cancer

The first reports suggesting an involvement of human papillomavirus (HPV) in the development of both benign and malignant squamous cell tumours of the oesophagus date back to 1982. Since then, a substantial amount of literature has accumulated on this subject, summarised in this review. To date, 239 oesophageal squamous cell papillomas have been analysed in 29 separate studies using different HPV detection methods, with HPV being detected in 51 (21.3%) cases. Many more squamous cell carcinomas have been analysed: of the 1485 squamous cell carcinomas analysed by in situ hybridisation, 22.9% were positive for HPV DNA, as were 15.2% of the 2020 cases tested by the polymerase chain reaction. In addition, evidence derived from large scale serological studies, animal experiments, and in vitro studies is discussed in the light of the highly variable geographical incidence rates of oesophageal carcinoma worldwide. It may be that the (multifactorial) aetiology of oesophageal cancer differs greatly between those geographical areas with a low risk and those with a high risk for this disease. Oncogenic HPV types seem to play an important causal role, particularly in high risk areas.

HPV infections and oesophageal cancer

The first reports suggesting an involvement of human papillomavirus (HPV) in the development of both benign and malignant squamous cell tumours of the oesophagus date back to 1982. Since then, a substantial amount of literature has accumulated on this subject, summarised in this review. To date, 239 oesophageal squamous cell papillomas have been analysed in 29 separate studies using different HPV detection methods, with HPV being detected in 51 (21.3%) cases. Many more squamous cell carcinomas have been analysed: of the 1485 squamous cell carcinomas analysed by in situ hybridisation, 22.9% were positive for HPV DNA, as were 15.2% of the 2020 cases tested by the polymerase chain reaction. In addition, evidence derived from large scale serological studies, animal experiments, and in vitro studies is discussed in the light of the highly variable geographical incidence rates of oesophageal carcinoma worldwide. It may be that the (multifactorial) aetiology of oesophageal cancer differs greatly between those geographical areas with a low risk and those with a high risk for this disease. Oncogenic HPV types seem to play an important causal role, particularly in high risk areas.

Building bridges in cancer: mismatch repair and microsatellite instability

Mismatch repair (MMR) defects and microsatellite instability (MSI) are two genetic alterations that have been documented in a wide variety of human cancers, including some that involve the skin. Available evidence indicates that these two features are sometimes directly related, although their connection seems to be indirect or nonexistent in other instances. The purposes of this review are to summarize the variable relations between MMR and MSI as deduced from analysis of a diverse array of human neoplasms and to give brief insights as to the other molecular mechanisms potentially involved in the maintenance of genomic stability.

Selected novel anticancer treatments targeting cell signaling proteins

Empirical approaches to discovery of anticancer drugs and cancer treatment have made limited progress in the cure of cancer in the last several decades. Recent advances in technology and expanded knowledge of the molecular basis of tumorigenesis and metastasis have provided unique opportunities to design novel compounds that rationally target the abnormal molecular and biochemical signals leading to cancer. Several such novel agents have completed advanced stages in clinical development. The excellent clinical results achieved by some of these compounds are creating new paradigms in management of patients with neoplastic diseases. Clinical development of these agents also raises challenges to the traditional methods of drug evaluation and measurement of efficacy.

Clinicopathologic and molecular analysis of high-grade dysplasia and early adenocarcinoma in short- versus long-segment Barrett esophagus

Barrett esophagus, especially dysplastic Barrett mucosa, has been regarded as a preneoplastic lesion for esophageal adenocarcinoma. However, the etiology and pathogenesis of dysplasia and early adenocarcinoma in short- (SSBE) and long- (LSBE) segment Barrett esophagus have not been studied in detail. The aims of this study were to clarify clinicopathologic and genetic differences between high-grade dysplasia (HGD) and early adenocarcinoma in SSBE versus LSBE. We analyzed the clinicopathologic features from 47 patients (19 SSBE [<3 cm] and 28 LSBE [> or =3 cm]) with esophagectomy for HGD/T1 adenocarcinoma. Allelic losses on chromosomes 3p (FIHT), 5q (APC), 9p (p16), and 17p (p53) were compared in 12 HGD and 9 T1 tumors from 19 cases of SSBE and in 23 HGD and 15 T1 tumors from 28 cases of LSBE. Patients with SSBE were more likely to be smokers than were patients with LSBE (94.7% v 57.1%; P =.004). HGD or T1 tumors arising from SSBE were less likely to show adjoining nondysplastic Barrett mucosa than those from LSBE (73.6% v 100%; P =.02). LSBE more frequently showed a circumferential pattern of Barrett mucosa than did SSBE (96.4% v 47.3%; P =.0002). Chromosomal allelic losses on 3p, 5q, 9p, and 17p were detected in 19% (4 of 21), 43% (15 of 35), 40% (14 of 35), and 48% (16 of 33) of HGD, respectively, and 26% (5 of 19), 35% (8 of 23), 35% (8 of 23), and 57% (13 of 23) of T1 tumor, respectively. There were no significant differences in allelic loss of 3p, 5q, 9p, or 17p in HGD or T1 tumors from SSBE versus LSBE. These results suggest that both HGD and early adenocarcinoma in SSBE and LSBE may occur through similar genetic alterations, whereas there are some clinicopathologic differences between SSBE and LSBE. HUM PATHOL

Molecular alterations of Barrett's esophagus on microdissected endoscopic biopsies

Alterations in proto-oncogenes and tumor suppressor genes play a role in the sequence from Barrett's metaplasia to esophageal adenocarcinoma. The present study aims to ascertain whether molecular abnormalities take place in Barrett's metaplasia and low-grade dysplasia and to correlate them with the histological features of the esophageal mucosa. Forty-one formalin-fixed, paraffin-embedded endoscopic esophageal biopsies were classified according to the type of metaplastic changes (noncolumnar fundic and cardial metaplasia; columnar metaplasia, with and without intestinal features). After microdissection samples were examined for loss of heterozygosity (LOH) using polymorphic markers on 5q (D5S82), corresponding to APC (adenomatous polyposis coli) gene, 13q (CA repeat in intron 2 position 14815 to 14998 of the retinoblastoma gene), 17p (D17S513) corresponding to p53 locus, and for p53 mutations. Molecular alterations including LOH, allelic imbalance, and microsatellite instability could be detected in all types of metaplastic changes and sporadically in the squamous epithelium adjacent to the metaplastic tissue. Molecular alterations involving microsatellites D5S82 and the CA repeat inside the retinoblastoma gene were more frequent in nonintestinal metaplasia whereas those involving the p53 locus took place in columnar intestinal metaplasia and in low-grade dysplasia. Clonal changes were demonstrated in different metaplastic areas in three patients. Genetic alterations comprising LOH and microsatellite instability characterize Barrett's mucosa and appear related to the type of metaplastic change. Some of them precede the development of intestinal metaplasia, suggesting that genetic alterations take place earlier than previously thought.

Nonrandom chromosomal imbalances in esophageal squamous cell carcinoma cell lines: possible involvement of the ATF3 and CENPF genes in the 1q32 amplicon

Using comparative genomic hybridization (CGH), we investigated copy number aberrations in 29 esophageal squamous cell carcinoma (ESC) cell lines. All lines displayed numerous chromosome imbalances. The most frequent losses were observed on chromosome 18q (65.5%), Xp (48. 3%), 3p (44.8%), 4q (44.8%), 8p (41.4%), 11q23 - 25 (34.5%) and 4p (27.6%), whereas the most common copy number gains were noted at 8q (86.2%), 3q (82.8%), 5p (69%), 7p (69%), 20q (65.5%), 9q (55.2%), 11q (55.2%), 1q (48.3%), Xq (44.8%) and 18p (37.9%). High-level gains (HLGs) were detected at 3q26 (9 cases), 8q23 (6 cases), 5p14 - 15 (6 cases), 18p11.2 - 11.3 (6 cases), 3q27 - 28 (5 cases), 5p13 (3 cases), 7p14 - 15 (3 cases), 20q12 - 13 (3 cases), 11q13 (3 cases), 14q21 (2 cases), 20p11.2 (2 cases), 13q32 (2 case), and 1q32 (1 case). Among them, HLGs of 1q32 have been reported in other types of cancer, including glioblastoma and breast cancers. We successfully narrowed down the smallest common amplicon involving 1q-gain to the genomic segment between D1S414 and D1S2860 by fluorescence in situ hybridization (FISH). Southern and northern blot analysis clearly demonstrated that ATF3, human activating transcription factor-3 and CENPF, centromere protein F, mapped within this region, were significantly amplified and over-expressed in 1q32 amplicon.

Mutations in beta-catenin and APC genes are uncommon in esophageal and esophagogastric junction adenocarcinomas

Beta-catenin plays important roles in both intercellular adhesion and signal transduction. Mutations in the beta-catenin or adenomatous polyposis coli (APC) gene can alter the degradation of beta-catenin and cause aberrant accumulation of beta-catenin result in increased transcription of target genes. The dysregulated APC/beta-catenin pathway has been recently discovered as an important mechanism of tumorigenesis in various cancers, but its role in esophageal adenocarcinomas is not clear. Therefore, we studied the beta-catenin gene mutation, allelic loss of chromosome 5q, and APC gene mutation in esophageal and esophagogastric junction adenocarcinomas. Two (2%) somatic mutations in exon 3 of the beta-catenin gene, encompassing the region for glycogen synthase kinase-3beta phosphorylation, were detected from 109 adenocarcinomas. Chromosomal allelic loss on 5q was frequent in 45.3% (44/97) of tumors. Only one missense mutation in the mutation cluster region of the APC gene was detected from 38 esophageal and esophagogastric junction adenocarcinomas with the 5q allelic loss. Our results based on partial screening mutational analyses indicate that mutations of APC/beta-catenin pathway, unlike in colorectal carcinoma, involve only a small subset of esophageal and esophagogastric junction adenocarcinoma.

Gains of 8q23-qter and 20q and loss of 11q22-qter in esophageal squamous cell carcinoma associated with lymph node metastasis

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is associated with poor prognosis and lymph node metastasis is one of the critical prognostic factors. Although it is important to elucidate the genetic aberrations underlying its lymph node metastasis, to the authors' knowledge little is known regarding alterations in the primary ESCC that are linked with ESCC metastasis to the lymph nodes.

METHODS

To elucidate genetic aberrations involved in the lymph node metastasis of ESCC, comparative genomic hybridization analysis was applied to 36 ESCC specimens, from 12 cases with no lymph node metastasis and 24 cases with lymph node metastasis.

RESULTS

Copy number gains frequently were detected at 3q (75%), 8q23-qter (50%), 11q13 (44%), 5p14-pter (25%), 20q (25%), 7q (22%), 2p (19%), 12p (17%), and 20p (17%) and losses were detected at 18q (58%), 3p (50%), 9p (44%), 5q14-23 (39%), 4q (33%), 13q (22%), and 11q22-qter (19%). DNA amplifications were detected at four loci: 11q13, 2q12, 7q21, and 20q11.2 It is interesting to note that the gains of 8q23-qter (P < 0.0005) and 20q (P < 0.02) and loss of 11q22-qter (P < 0.05) were observed in tumors metastatic to the lymph nodes. The gains of 3q and 11q13 and losses of 18q, 3p, 9p, 5q14-23, and 4q were detected in both early and advanced stage ESCCs.

CONCLUSIONS

These observations suggest that gains of 8q23-qter and 20q and loss of 11q22-qter allow the prediction of lymph node metastasis, and that gains of 3q and 11q13 and losses of 18q, 3p, 9p, 5q14-23, and 4q are associated with the development of ESCC.

Molecular cytogenetic fingerprinting of esophageal squamous cell carcinoma by comparative genomic hybridization reveals a consistent pattern of chromosomal alterations

Esophageal cancer is the third most prevalent gastrointestinal malignancy in the world. The tumor responds poorly to various therapeutic regimens and the genetic events underlying esophageal carcinogenesis are not well understood. To identify overall chromosomal aberrations in esophageal squamous cell carcinoma, we performed comparative genomic hybridization (CGH). All 17 tumor samples were found to exhibit multiple gains and losses involving different chromosomal regions. The frequency of chromosomal loss associated with this type of tumor was as follows: in 2q (100%), 3p (100%), 13q (100%), Xq (94%), 4 (82%), 5q (82%), 18q (76%), 9p (76%), 6q (70%), 12q (70%), 14q (65%), 11q (59%), and 1p (53%). Interstitial deletions on 1p, 3p, 5q, 6q, 11q, and 12q were detected also. Chromosomal gains were displayed by chromosomes and chromosome areas: 19 (100%), 20q (94%), 22 (94%), 16p (65%), 17 (59%), 12q (59%), 8q (53%), 9q (53%), and 3q (50%). Two sites showing apparent amplification were 11q (70%) and 5p15 (47%). To validate the CGH data, we isolated a BAC clone mapping to 18q12.1. This clone was used as a probe in interphase fluorescence in situ hybridization of tumor touch preparations and allelic loss was clearly revealed. This study represents the first whole-genome analysis in esophageal squamous cell carcinoma for associated chromosomal aberrations that may be involved in either the genesis or progression of this malignancy.

Apoptosis in esophageal cancer following induction chemoradiotherapy

BACKGROUND

The poor survival of patients with esophageal cancer following esophagectomy has led to intense investigation into combined modality therapy. Based on results from clinical trials examining chemoradiotherapy alone without surgery, resection has come under increased scrutiny and its necessity as a component of a multimodal approach has been questioned. In this study, we examined whether residual tumor cells in esophagectomy specimens following induction chemoradiotherapy are viable and, therefore, provide putative evidence for the appropriateness of esophagectomy.

MATERIALS AND METHODS

Between August 1991 and January 1995, 46 patients were entered into an induction chemoradiotherapy trial consisting of 5-fluorouracil, cisplatin, alpha-interferon, and concurrent external beam radiotherapy followed by esophagectomy. Response was determined histologically and apoptosis assessed with a terminal deoxytransferase assay system. p53 status was determined by immunohistochemistry and mutational analysis.

RESULTS

Thirty-eight patients underwent esophagectomy, 33 of whom had either a complete (n = 10) or partial (n = 23) response. None of the 28 patients with residual tumor in the resected specimen had 100% apoptotic cells and the vast majority of specimens had less than a 10% apoptotic rate. The percentage of apoptotic cells did correlate with tumor differentiation but not with histologic type nor presence of p53 mutations.

CONCLUSIONS

These data suggest that resection following upfront chemoradiotherapy is a necessary component of a multimodality approach to esophageal cancer and will ultimately provide superior local-regional control to a nonsurgical approach.

Genetic alterations in Barrett esophagus and adenocarcinomas of the esophagus and esophagogastric junction region

The incidence of esophageal adenocarcinoma has increased markedly in the past two decades, but the genetic alterations in this cancer and its precursor, Barrett mucosa, have not been characterized extensively. DNA replication errors and allelic losses of chromosomes 17p, 18q, and 5q were studied in 36 resected adenocarcinomas arising in the esophagus and esophagogastric junction, 56 Barrett adenocarcinomas, and 11 dysplasias in Barrett esophagus. The results were compared with clinical and pathological characteristics, including patient survival. Replication error positive cancer was rare (5.4%) in esophageal adenocarcinomas and was not found in Barrett mucosa. There was an increase in the prevalence of chromosomal losses in the Barrett mucosa-columnar dysplasia-adenocarcinoma sequence: 17p loss occurred in 14% of Barrett mucosae, 42% of low-grade dysplasias, 79% of high-grade dysplasias, and 75% of adenocarcinomas, respectively; loss of 18q in 32%, 42%, 73%, and 69%; and loss of 5q in 10%, 21%, 27%, and 46%. Clinical stage was a very strong prognostic factor for survival, and adenocarcinomas with allelic loss of both 17p and 18q had worse survival than cancers with no or one allelic loss (P = 0.002). Our results indicate that accumulation of genetic alterations follows the dysplasia-adenocarcinoma sequence in the esophagus and that losses of 18q and 17p occur earlier than 5q loss. Allelic loss of both 17p and 18q in esophageal adenocarcinoma identifies patients with poor prognosis.