Identification of EGFR and KRAS mutations in Chinese patients with esophageal squamous cell carcinoma

Bone metastatic carcinoma with EGFR amplification and mutation: A case report and literature review

RATIONALE

Mutations in the epidermal growth factor receptor (EGFR) gene are highly prevalent in non-small cell lung cancer, while rare in other cancers. Primarily it's hardly present in bone metastases from cancer of unknown primary (BMCUP). Currently, no specific treatment options for bone metastases from unknown primary cancers exist.

PATIENT CONCERNS

The right shoulder and back pain of a 72-years-old man had been persistent for 2 weeks and had developed worse on 1 particular day. The right upper arm was compromised, which also hindered the arm's ability to raise and flex, and nighttime sleep was impacted. After applying the analgesic patch externally, the symptoms did not improve. No coughing or sputum production, chest tightness, shortness of breath, acid reflux, belching, abdominal pain, distension, diarrhea, backache, hematuria, black or bloody feces, or other discomforts appeared over the course of the illness.

DIAGNOSES

The patient had a particular type of bone metastases from primary cancers with genetic test results indicating EGFR amplification and mutation.

INTERVENTIONS

A third-generation tyrosine kinase inhibitors drug, oral Osimertinib 80 mg once a day with bisphosphonates anti-bone destruction treatment was performed on schedule.

OUTCOMES

Following treatment, the patient's tumor-related symptoms were significantly improved by controlling the disease for up to 11 months and providing great pain relief.

LESSON

EGFR-based genetic testing has emerged as a key measure for targeted therapy in non-small cell lung cancer. However, there are fewer relevant studies for other tumor types like BMCUP. Combined with literature reviews and our report, we provide evidence that targeting EGFR mutations according to the "basket theory" for the treatment of BMCUP is effective.

Cross-talk between next generation sequencing methodologies to identify genomic signatures of esophageal cancer

The asymptomatic behaviour of esophageal cancerous cells at early stages develops advanced clinical presentation of the disease, resulting in poor prognosis and curbed intervention of therapeutic modalities. The endeavours to detect diagnostic and prognostic markers have been proven futile at the clinical platform. While several biomarkers have been investigated, including CYFRA 21-1, carcinoembryonic antigen and squamous cell carcinoma antigen, their sensitivity has not proved consistently satisfactory across the various stages of esophageal cancer. Hence, there is an impending requirement of biomarkers for early diagnosis and better prognosis. In the recent past, next generation sequencing (NGS) tool has emerged as an important tool to highlight the hallmarks of esophageal cancer (EC). This review summarizes the changes/mutations occurred in tumor cells during carcinogenesis and addresses the contribution of NGS techniques, viz. whole genome sequencing (WGS), RNA-Sequencing and Exome sequencing (ES), in EC. Additionally, this review highlights the connection between the findings from these techniques. An effort has been made to emphasize the genes affected and involved signaling pathway in EC. Further, investigations of these mutated genes would not only shed light on the relevant genes to be studied but also help in the better management and cure through personalized therapy.

Mutations in foregut SOX2+ cells induce efficient proliferation via CXCR2 pathway

Identification of the precise molecular pathways involved in oncogene-induced transformation may help us gain a better understanding of tumor initiation and promotion. Here, we demonstrate that SOX2⁺ foregut epithelial cells are prone to oncogenic transformation upon mutagenic insults, such as Kras^G12D and p53 deletion. GFP-based lineage-tracing experiments indicate that SOX2⁺ cells are the cells-of-origin of esophagus and stomach hyperplasia. Our observations indicate distinct roles for oncogenic KRAS mutation and P53 deletion. p53 homozygous deletion is required for the acquisition of an invasive potential, and Kras^G12D expression, but not p53 deletion, suffices for tumor formation. Global gene expression analysis reveals secreting factors upregulated in the hyperplasia induced by oncogenic KRAS and highlights a crucial role for the CXCR2 pathway in driving hyperplasia. Collectively, the array of genetic models presented here demonstrate that stratified epithelial cells are susceptible to oncogenic insults, which may lead to a better understanding of tumor initiation and aid in the design of new cancer therapeutics.

Targeting p21-activated kinase 1 inhibits growth and metastasis via Raf1/MEK1/ERK signaling in esophageal squamous cell carcinoma cells

Background

p21-activated kinase 1 (PAK1) plays a fundamental role in promoting the development and progression of several cancers and is a potential therapeutic target. However, the biological function and underlying mechanism of PAK1 in esophageal squamous cell carcinoma (ESCC) remain unclear.

Methods

The expression of PAK1 was detected in both ESCC cell lines and clinical samples. Cell growth was measured by MTT, focus formation and soft agar assays. Cell migration and invasion were detected by wound healing and transwell assays. Animal models of subcutaneous tumourigenicity and tail vein metastasis were performed to determine the inhibitory effect of pharmacological inhibitor IPA-3 on tumor growth and metastasis of ESCC cells.

Results

We found that PAK1 was frequently overexpressed in ESCC. Ectopic expression of PAK1 promoted cellular growth, colony formation and anchorage-independent growth. Overexpressing PAK1 also enhanced migration, invasion and the expression of MMP-2 and MMP-9 in ESCC cells. In contrast, silencing PAK1 by lentiviral knockdown or a specific inhibitor IPA-3 resulted in a contrary effect. Subsequent investigations revealed that Raf1/MEK1/ERK signaling pathway was involved in PAK1-mediated effect. Enhanced expression of Raf1 attenuated the inhibitory functions of PAK1 shRNA. Whereas blocking of Raf1 by shRNA or specific inhibition of MEK1 by U0126 antagonized the oncogenetic effect of PAK1 on ESCC cells. More importantly, Pharmacological inhibition of PAK1 by IPA-3 significantly suppressed tumor growth and lung metastasis of ESCC cells in vivo.

Conclusions

These data support that PAK1 is an ideal target for the development of potential therapeutic drugs for ESCC patients even with metastasis.

Electronic supplementary material

The online version of this article (10.1186/s12964-019-0343-5) contains supplementary material, which is available to authorized users.

lncRNA LINC00152 knockdown had effects to suppress biological activity of lung cancer via EGFR/PI3K/AKT pathway

Accumulating evidence demonstrates that lncRNAs play important roles in regulating gene expression and are involved in various pathological processes. In our present study, we firstly evaluated lncRNA LINC00152 and EGFR expressions by ISH or IHC methods, and analyzed the correlation between LINC00152 and EGFR with RT-PCR. lncRNA LINC00152 of NSCLC tissues were significantly up-regulation compared with adjacent normal tissues and positively correlated with EGPR. The further cell experiments demonstrated that Linc00152 knockdown had effects of suppression cell proliferation, invasion and migration abilities and improving cell apoptosis and G1 phase rates in both A549 and H1299 cell lines. In the mechanism study, the results were shown that EGFR, PI3K, AKT, Fibronectin and Vimentin proteins expressions were significantly reduced and P21 protein expression was significantly increased in Linc00152 knockdown groups. Our results suggested lncRNA LINC00152 knock-down had anti-tumor effects via EGFR/PI3K/AKT pathway.

Chromosomal and Genomic Variations in Esophageal Squamous Cell Carcinoma: A Review of Technologies, Applications, and Prospections

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors with poor prognosis worldwide. The poor prognosis is due to the advanced stage at the time of diagnosis and the limited clinical staging lacking significant molecular biomarkers to effectively stratify patients for treatment options. As cancer is a disease of genome instability and a resulting of accumulation of genetic alteration, mounting chromosomal and genomic technologies were developed and progressed rapidly which could be used for characterizing patients in genomics level. In this review, we summarized applications of multiple technologies and research progress at chromosomal and genomic level in ESCC.

Integrated molecular analysis reveals complex interactions between genomic and epigenomic alterations in esophageal adenocarcinomas

The incidence of esophageal adenocarcinoma (EAC) is rapidly rising in the United States and Western countries. In this study, we carried out an integrative molecular analysis to identify interactions between genomic and epigenomic alterations in regulating gene expression networks in EAC. We detected significant alterations in DNA copy numbers (CN), gene expression levels, and DNA methylation profiles. The integrative analysis demonstrated that altered expression of 1,755 genes was associated with changes in CN or methylation. We found that expression alterations in 84 genes were associated with changes in both CN and methylation. These data suggest a strong interaction between genetic and epigenetic events to modulate gene expression in EAC. Of note, bioinformatics analysis detected a prominent K-RAS signature and predicted activation of several important transcription factor networks, including β-catenin, MYB, TWIST1, SOX7, GATA3 and GATA6. Notably, we detected hypomethylation and overexpression of several pro-inflammatory genes such as COX2, IL8 and IL23R, suggesting an important role of epigenetic regulation of these genes in the inflammatory cascade associated with EAC. In summary, this integrative analysis demonstrates a complex interaction between genetic and epigenetic mechanisms providing several novel insights for our understanding of molecular events in EAC.

Genomic characterization of esophageal squamous cell carcinoma: Insights from next-generation sequencing

Two major types of cancer occur in the esophagus: squamous cell carcinoma, which is associated with chronic smoking and alcohol consumption, and adenocarcinoma, which typically arises in gastric reflux-associated Barrett’s esophagus. Although there is increasing incidence of esophageal adenocarcinoma in Western counties, esophageal squamous cell carcinoma (ESCC) accounts for most esophageal malignancies in East Asia, including China and Japan. Technological advances allowing for massively parallel, high-throughput next-generation sequencing (NGS) of DNA have enabled comprehensive characterization of somatic mutations in large numbers of tumor samples. Recently, several studies were published in which whole exome or whole genome sequencing was performed in ESCC tumors and compared with matched normal DNA. Mutations were validated in several genes, including in TP53, CDKN2A, FAT1, NOTCH1, PIK3CA, KMT2D and NFE2L2, which had been previously implicated in ESCC. Several new recurrent alterations have also been identified in ESCC. Combining the clinicopathological characteristics of patients with information obtained from NGS studies may lead to the development of effective diagnostic and therapeutic approaches for ESCC. As this research becomes more prominent, it is important that gastroenterologist become familiar with the various NGS technologies and the results generated using these methods. In the present study, we describe recent research approaches using NGS in ESCC.

Synergistic effect of targeting the epidermal growth factor receptor and hyaluronan synthesis in oesophageal squamous cell carcinoma cells

BACKGROUND AND PURPOSE

Worldwide, oesophageal cancer is the eighth most common cancer and has a very poor survival rate. In order to identify new tolerable treatment options for oesophageal squamous cell carcinoma (ESCC), erlotinib was tested with moderate efficacy in phase I and II studies. As 4-methylumbelliferone (4-MU), an hyaluronan (HA) synthesis inhibitor showed anti-cancer effects in vitro, and in ESCC xenograft tumours, we investigated whether the anti-cancer effects of erlotinib could be augmented by combining it with 4-MU.

EXPERIMENTAL APPROACH

ESCC cell lines were treated with erlotinib or gefitinib (1 μmol·L^-1 ) and 4-MU (300 μmol·L^-1 ), and the cell count, cell cycle progression and migration were determined as compared to the single agents and the solvent-control.

KEY RESULTS

The combination of erlotinib and 4-MU synergistically inhibited the proliferation of ESCC cell lines. Furthermore, the migration speed of ESCC cell line KYSE-410 in gap closure assays was significantly reduced by the combination of erlotinib and 4-MU. Decreased ERK phosphorylation could explain the anti-proliferative and anti-migratory effects in the combined treatment group. Finally, the combination was additionally able to decrease the growth of multicellular tumour spheroids, a three-dimensional cell culture model that was associated with sustained inhibition of ERK1/2 phosphorylation.

CONCLUSIONS AND IMPLICATIONS

The combination of 4-MU and erlotinib showed promising anti-cancer efficacies in the ESCC cell lines.

High-incidence of PTEN mutations in Chinese patients with primary small cell carcinoma of the esophagus

Background

Primary small cell carcinoma of the esophagus (PSCCE) is a rare and aggressive tumor with poor prognosis. The aim of this study was to investigate the existence of EGFR, KRAS, PIK3CA and PTEN mutations in PSCCE.

Methods

Clinical–pathological data and paraffin-embedded specimens were collected from 38 patients. Exons 18 to 21 of EGFR, KRAS and PIK3CA status were analyzed by real-time PCR based on ARMS and Scorpion technology in all patients, and the PTEN gene was also screened using real-time PCR and high-resolution melting curve analysis (HRMA).

Results

Only 1 (2.63%) out of 38 patients had EGFR mutations in L858R missense, and KRAS and PIK3CA were not found in the mutational spot in all patients. However, PTEN mutations presented in 14 (36.84%) out of 38 patients, including exon 5 coding for PTEN missense mutation (n =4, 10.53%), exon 6 (n =7, 18.42%), concurrent exon 5 and exon 6 (n =2, 5.26%), and exon 8 (n =1, 2.63%). Concurrent mutations of these genes were not detected in all samples. No statistically significant associations were found between the clinicopathological features and the mutation status of PTEN.

Conclusions

The incidence of PTEN mutations in Chinese patients with PSCCE was higher than that of previous reports in other histological subtypes of esophageal cancer.

KRAS and BRAF mutations in 203 esophageal squamous cell carcinomas: pyrosequencing technology and literature review

BACKGROUND

Epidermal growth factor receptor (EGFR) signaling is one of the most promising targets for molecular-targeted therapies in esophageal squamous cell carcinoma (ESCC). Thus, the molecular diagnosis of KRAS and BRAF mutations is clinically important in therapeutic decision making. However, the frequency of KRAS and BRAF mutations in ESCCs remains inconclusive because of the limited sample sizes of previous studies (all N ≤ 80). Pyrosequencing is a nonelectrophoretic nucleotide extension sequencing technology that can be used for mutation testing.

METHODS

The frequency of KRAS and BRAF mutations was examined using a nonbiased database of 203 resected ESCCs and a high-throughput pyrosequencing assay.

RESULTS

The validity of the KRAS pyrosequencing method was initially demonstrated by detection of all 4 types of KRAS mutations [c.35G>T (codon 12 GGT>GTT), c.35G>A (codon 12 GGT>GAT), c.34G>T (codon 12 GGT>TGT), c.38G>A mutation (codon 13 GGC>GAC)], which had been previously diagnosed using Scorpion-ARMS technology, in 9 colon cancer tissues (9 of 9; 100 %). Similar results were demonstrated for BRAF mutational status in 3 colon cancer cell lines (HCT116, Colo201, and HT29), which were validated by Sanger dideoxy sequencing. Subsequently, the KRAS mutation was found to be extremely rare (1 of 203; 0.5 %), and the BRAF mutation was absent (0 of 203; 0 %), in the dataset of 203 ESCCs.

CONCLUSIONS

These results suggest that KRAS and BRAF mutations play a limited role in the development of ESCC and that mutation analysis is not useful as a screening test for sensitivity to anti-EGFR therapy in ESCC.

Identification of exon 19 and 21 mutations of EGFR gene in Chinese patients with esophageal squamous cell carcinoma

BACKGROUND

Although epidermal growth factor receptor (EGFR) inhibitor treatment showed modest response in several clinical trials in esophageal squamous cell carcinoma (ESCC) patients, it has been reported that the frequency of EGFR mutations varied largely. The aim of this study was to investigate the existence of EGFR mutations in Chinese esophageal squamous cell carcinomas.

METHODS

Formalin-fixed paraffin-embedded surgically resected tumor samples were obtained from 127 randomly selected Chinese patients with ESCC. The most common EGFR mutations, including in-frame deletions in exon 19 and base substitutions in exon 21, were detected by denaturing high performance liquid chromatography (DHPLC) and direct sequencing simultaneously. K-RAS mutations in codons 12 and 13 were detected by direct sequencing.

RESULTS

In this study, L858R missense mutations of the EGFR gene were found in 8 out of 127 patients (6.3%) by DHPLC but no mutation was observed by direct sequencing. In addition, K-RAS mutation was detected in 2 out of 127 (1.6%) patients by direct sequencing.

CONCLUSIONS

The incidence of EGFR mutations was relatively high using DHPLC method but no mutation with direct sequencing in Chinese ESCC patients.

MALDI imaging on large-scale tissue microarrays identifies molecular features associated with tumour phenotype in oesophageal cancer

AIMS

Matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI) and tissue microarray (TMA) technologies were jointly utilized to search for molecular features associated with clinicopathological parameters in oesophageal cancer.

METHODS AND RESULTS

Two TMAs from formalin-fixed tissue samples, including 300 adenocarcinomas and 177 squamous cell carcinomas with clinical follow-up data, were analysed. MALDI-MSI analysis revealed 72 distinct mass per charge (m/z) signals associated with tumour cells, 48 of which were found in squamous cell carcinomas only, and 12 of which were specific for adenocarcinomas. In adenocarcinomas, six signals were linked to early-stage (pT1-T2) tumours (two signals) and the presence (one signal) or absence (three signals) of lymph node metastasis. In squamous cell carcinomas, 24 signals were strongly linked to different phenotypic features, including tumour stage (four signals), histological grade (four signals), and lymph node metastasis (three signals).

CONCLUSIONS

The high number of m/z signals that were found to be significantly linked to one or more phenotypic features of oesophageal cancer highlights the power of MALDI-MSI in the analysis of high-density TMAs. The data also emphasise substantial biological differences between adenocarcinomas and squamous cell carcinomas.

Genomic alterations in advanced esophageal cancer may lead to subtype-specific therapies

The development of targeted agents for metastatic esophageal or gastroesophageal junction (GEJ) tumors has been limited when compared with that for other common tumors. To date, the anti-human epidermal growth factor receptor-2 (HER-2) antibody, trastuzumab, in combination with chemotherapy, is the only approved novel agent for these cancers, and its use is limited to the small population of patients whose tumors overexpress HER-2. Despite recent progress in the field, median overall survival remains only 8-12 months for patients with stage IV esophageal or GEJ cancer. In this article, we examine the molecular aberrations thought to drive the development and spread of esophageal cancer and identify promising targets for specific tumor inhibition. Data from clinical studies of targeted agents are reviewed, including epidermal growth factor receptor antibodies, tyrosine kinase inhibitors, HER-2, and vascular endothelial growth factor-directed therapy. Current and future targets include MET, fibroblast growth factor receptor, and immune-based therapies. Evidence from trials to date suggests that molecularly unselected patient cohorts derive minimal benefit from most target-specific agents, suggesting that future collaborative investigation should focus on preselected molecular subgroups of patients with this challenging heterogeneous disease.

Alterations in epidermal growth factor receptors 1 and 2 in esophageal squamous cell carcinomas

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) shows a 5-year survival rate below 10%, demonstrating the urgency in improving its treatment. Alterations in epidermal growth factor receptors are closely related to malignancy transformation in a number of tumors and recent successful targeted therapies have been directed to these molecules. Therefore, in this study, we analyzed the expression of EGFR and HER2 and evaluated EGFR mutation profile as well as the presence of mutations in hotspots of KRAS and BRAF in ESCC patients.

METHODS

We performed RT-qPCR, immunohistochemistry and Fluorescent in situ hybridization to determine EGFR and HER2 expression in ESCC patients, and direct sequencing and PCR-RFLP for mutations and polymorphism analysis.

RESULTS

Our results showed an increased EGFR mRNA expression in tumors compared to surrounding tissue (p <0.05), with 11% of the cases presenting at least a four-fold difference between tumor and paired adjacent mucosa. EGFR protein overexpression was present only in 4% of the cases. The median expression of HER2 mRNA was not different between tumors and adjacent mucosa. Still, 7% of the tumors presented at least a 25-fold higher expression of this gene when compared to its paired counterpart. Immunohistochemical analysis revealed that 21% of the tumors were positive for HER2 (scores 2+ and 3+), although only 3+ tumors presented amplification of this gene. Mutation analysis for EGFR (exons 18-21), KRAS (codons 12 and 13) and BRAF (V600E) showed no mutations in any of the hotspots of these genes in almost 100 patients analyzed. EGFR presented synonymous polymorphisms at codon 836 (C>T) in 2.1% of the patients, and at codon 787 (G>A) in 79.2% of the cases. This last polymorphism was also evaluated in 304 healthy controls, which presented a similar frequency (73.7%) in comparison with ESCC patients. The absence of mutations of EGFR, KRAS and BRAF as well as the overexpression of EGFR and HER2 in less than 10% of the patients suggest that this signaling pathway is altered in only a small proportion of patients with ESCC.

CONCLUSION

HER receptors target therapies may have the potential to be effective in only a minor fraction of patients with ESCC.

Trastuzumab anti-tumor efficacy in patient-derived esophageal squamous cell carcinoma xenograft (PDECX) mouse models

BACKGROUND

Trastuzumab is currently approved for the clinical treatment of breast and gastric cancer patients with HER-2 positive tumors, but not yet for the treatment of esophageal carcinoma patients, whose tumors typically show 5 ~ 35% HER-2 gene amplification and 0 ~ 56% HER-2 protein expression. This study aimed to investigate the therapeutic efficacy of Trastuzumab in patient-derived esophageal squamous cell carcinoma xenograft (PDECX) mouse models.

METHODS

PDECX models were established by implanting patient esophageal squamous cell carcinoma (ESCC) tissues into immunodeficient (SCID/nude) mice. HER-2 gene copy number (GCN) and protein expression were determined in xenograft tissues and corresponding patient EC samples by FISH and IHC analysis. Trastuzumab anti-tumor efficacy was evaluated within these PDECX models (n = 8 animals/group). Furthermore, hotspot mutations of EGFR, K-ras, B-raf and PIK3CA genes were screened for in the PDECX models and their corresponding patient's ESCC tissues. Similarity between the PDECX models and their corresponding patient's ESCC tissue was confirmed by histology, morphology, HER-2 GCN and mutation.

RESULTS

None of the PDECX models (or their corresponding patient's ESCC tissues) harbored HER-2 gene amplification. IHC staining showed HER-2 positivity (IHC 2+) in 2 PDECX models and negativity in 3 PDECX models. Significant tumor regression was observed in the Trastuzumab-treated EC044 HER-2 positive model (IHC 2+). A second HER-2 positive (IHC 2+) model, EC039, harbored a known PIK3CA mutation and showed strong activation of the AKT signaling pathway and was insensitive to Trastuzumab treatment, but could be resensitised using a combination of Trastuzumab and AKT inhibitor AZD5363. In summary, we established 5 PDECX mouse models and demonstrated tumor regression in response to Trastuzumab treatment in a HER-2 IHC 2+ model, but resistance in a HER-2 IHC 2+/PIK3CA mutated model.

CONCLUSIONS

This study demonstrates Trastuzumab-induced tumor regressions in HER-2 positive tumors, and highlights PIK3CA mutation as a potential resistance mechanism to Trastuzumab treatment in pre-clinical patient-derived EC xenograft models.

pERK activation in esophageal carcinomas: clinicopathological associations

MAPK (mitogen-activated protein kinase) pathway is considered a control regulator in various malignant tumors but its role in esophageal carcinomas remains elusive. In our study, we examined the possible prognostic significance of MAPK pathway in human esophageal cancer. We searched for mutations in exons 18-21 of EGFR gene, codons 12 and 13 of K-RAS gene and exon 15 of B-RAF gene by high resolution melting analysis (HRMA) and pyrosequencing in 44 esophageal carcinomas. Immunohistochemistry was performed in 29 cases in order to evaluate expression levels of pERK (extracellular-signal regulated kinase). In one laser microdissected squamous cell carcinoma, a somatic K-RAS mutation at codon 12 was detected, whereas none of the cases displayed mutations in EGFR and B-RAF genes. Elevated nuclear as well as cytoplasmic pERK expression (100% and 62% of cases respectively) was observed independently of EGFR and B-RAF mutational status. Increasing pERK nuclear and cytoplasmic expression as well as the intensity of nuclear staining was found to be significantly correlated with tumor grade in univariate and multivariate statistical analysis. Our findings depict the presence of activated ERK despite the low frequency of upstream alterations, implicating ERK activation in the acquisition of a more aggressive phenotype in esophageal cancer.

Immunohistochemical and oncogenetic analyses of the esophageal basaloid squamous cell carcinoma in comparison with conventional squamous cell carcinomas

Basaloid squamous cell carcinoma of the esophagus is a rare variant of squamous cell carcinoma. We reviewed 878 cases of esophageal squamous cell carcinoma and detected 22 cases (3%) of basaloid squamous cell carcinoma. These tumors and stage-matched paired conventional squamous cell carcinomas were investigated for clinicopathologic features and immunoreactivity of cytokeratin subtypes, p53, B-cell lymphoma 2 (bcl-2), β-catenin, and epidermal growth factor receptor. Molecular aberrations in p53, CTNNB1 (the gene encoding β-catenin), and epidermal growth factor receptor (EGFR) were also determined. Patients with basaloid squamous cell carcinomas demonstrated a 5-year survival rate of 42%, significantly worse than those with well-differentiated squamous cell carcinoma (P<.01). Histologically, solid nests with central necrosis and a cribriform pattern were identified in almost all (≥95%) cases, and ductal differentiation was less frequent (45%) but associated with significantly better survival (P<.05). Compared with conventional squamous cell carcinomas, the basaloid squamous cell carcinomas were less immunoreactive for cytokeratin 14, cytokeratin 903, and membranous β-catenin (P<.01-.001) but more reactive for bcl-2, nuclear β-catenin, epidermal growth factor receptor, and Ki-67 (P<.05-.001). Direct sequencing showed mutations of p53 (36%), EGFR (14%), but not CTNNB1; fluorescent in situ hybridization detected amplification of the epidermal growth factor receptor gene (22%). In basaloid squamous cell carcinomas, low-level expression of cytokeratin 14/cytokeratin 903 and mutations of p53 and EGFR had a significant influence on worse survival (P<.05-.001). We conclude that the esophageal basaloid squamous cell carcinoma, a neoplasm with particularly aggressive biologic behavior, should be differentiated from conventional squamous cell carcinomas. In this context, immunohistochemical assessment of several markers might provide a useful adjunct diagnostic tool. Aberrations of p53 and epidermal growth factor receptor genes are possibly involved in progression of esophageal basaloid squamous cell carcinoma.