Epidermal growth factor receptor R497K polymorphism is a favorable prognostic factor for patients with colorectal carcinoma

Assessment of HER1 (rs11543848) and HER2 (rs1136201) polymorphism and their association with colorectal cancer susceptibility in Khyber Pakhtunkhwa, Pakistan

BACKGROUND

Colorectal cancer (CRC) is a widespread malignancy characterized by uncontrolled growth in the colon or rectum and remains a leading cause of cancer-related mortality globally. Various genes polymorphisms have been linked with the risk of CRC, but our study aimed to investigate the association between HER1 (rs11543848) and HER2 (rs1136201) polymorphisms with the risk of CRC in the Khyber Pakhtunkhwa (KPK) population of Pakistan. The association of the selected polymorphisms (rs11543848 and rs1136201) with CRC risk has been investigated in various ethnic groups, but their impact remains unexplored in Pakistan, particularly within the KPK population, highlighting the need of the study in this region.

METHODS

In this study 120 CRC patients and 120 healthy controls were enrolled. The DNA was extracted from the blood by salting-out method and genotyping was done using ARMS-PCR.

RESULTS

Our investigations provided convincing evidence of a strong association between HER1 (rs11543848) and the risk of CRC. Both the genotypes heterozygous GA (OR = 2.07, CI = 1.18 to 3.64, P = 0.01) and homozygous AA (OR = 6.22, CI = 2.56 to 15.08, P = 0.0001) showed higher risk and significant association with the CRC risk. Similarly, heterozygous genotype AG of HER2 (rs1136201) was significantly associated (OR = 3.16, 95% CI = 1.78 to 5.58, P = 0.0001) while mutant genotype GG showed higher risk but non-significant association (OR = 3.23, 95% CI = 0.84 to 12.43, P = 0.08) with CRC patients. HER1 (rs11543848) demonstrated a significant association (P = 0.003) with the age at diagnosis in CRC patients, while HER2 (rs1136201) showed a non-significant association (P = 0.434). Both the SNPs were non-significantly associated with gender (P = 0.793 and 0.117), metastasis (P = 0.582 and 0.129), location of the tumor (P = 0.555 and 0.993), tumor grade (P = 0.290 and 0.920), tumor size (P = 0.535 and 0.289) and stages of cancer (P = 0.892 and 0.352).

CONCLUSION

In conclusion, both the polymorphisms rs11543848 and rs1136201 displayed susceptibility with CRC in the KPK population. However, further investigations are recommended while using whole exome sequencing on a larger sample size for more precise results.

Polymorphisms in EGFR Gene Predict Clinical Outcome in Unresectable Non-Small Cell Lung Cancer Treated with Radiotherapy and Platinum-Based Chemoradiotherapy

For non-small cell lung cancer (NSCLC), radiotherapy (RT) and platinum-based chemotherapy (CHT) are among the main treatment options. On the other hand, radioresistance and cytotoxic drug resistance are common causes of failure. The epidermal growth factor receptor (EGFR) plays an important role in radioresponse and therapy resistance. We hypothesized that single nucleotide polymorphisms (SNPs) in the EGFR gene might affect individual sensitivity to these treatments, and thus, therapy outcome and prognosis. The association between functional EGFR SNPs and overall (OS), locoregional recurrence-free (LFRS), and metastasis-free (MFS) survival was examined in 436 patients with unresectable NSCLC receiving RT and platinum-based CHTRT. In a multivariate analysis, the rs712830 CC homozygotes showed reduced OS in the whole group (p = 0.039) and in the curative treatment subset (p = 0.047). The rs712829 TT genotype was strongly associated with decreased LRFS (p = 0.006), and the T-C haplotype was a risk factor for locoregional recurrence in our patients (p = 0.003). The rs2227983 GG alone and in combination with rs712829 T was an indicator of unfavorable LRFS (p = 0.028 and 0.002, respectively). Moreover, significant independent effects of these SNPs on OS, LRFS, and MFS were observed. Our results demonstrate that inherited EGFR gene variants may predict clinical outcomes in NSCLC treated with DNA damage-inducing therapy.

Genetic variants of the EGFR ligand-binding domain and their association with structural alterations in Arab cancer patients

Objective

This study aimed to identify novel genetic variants in the CR2 extracellular domain of the epidermal growth factor receptor (EGFR) in healthy individuals and patients with six different types of adenocarcinoma, in Arabian peninsula populations. It also aimed to investigate the effects of these variants on the EGFR structure and their eventual relevance to tumorigenesis.

Results

We detected seven new EGFR genetic variants in 168 cancer patients and 114 controls. A SNP rs374670788 was more frequent in bladder cancer but not significantly associated to. However, a missense mutation (V550M) was significantly associated to colon, ovary, lung, bladder and thyroid cancer samples (p < 0.05). Three mutations (H590R, E602K and T605T) were found in the heterozygous form only in colon cancer patients. Genomic analysis of the synonymous mutation (G632G) showed that the T/A genotype could be associated to thyroid cancer in Arab patients (p < 0.05). An additional novel SNP rs571064657 was observed in control individuals. Computational analysis of the genetic variants revealed a reduction in the stabilization of the EGFR tethered form for both V550M and the common R521K variant with low energetic state (− ∆∆G). Molecular interactions analysis suggested that these mutations might affect the receptor’s function and promote tumorigenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05559-y.

GENETIC POLYMORPHISM OF RETROPERITONEAL MYXOID LIPOSARCOMA

Objective: to detect new molecular genetic markers and therapeutic targets in retroperitoneal myxoid liposarcoma.

Material and Methods. DNA samples isolated from tumor tissue and obtained from formalinfixed paraffin-embedded (FFPE) slides were used. DNA was extracted using the GeneRead DNA FFPE Kit (50) (Qiagen). High-throughput next generation sequencing (NGS) using the GeneReader Actionable Insights Tumor Panel (GRTP – 101X) on the QCI Analyzer version 1.1 platform (Qiagen) was used for molecular genetic analysis of 12 genes involved in carcinogenesis: KRAS, NRAS, KIT, BRAF, PDGFRA, ALK, EGFR, ERBB2, PIK3CA, ERBB3, ESR1, RAF1.

Results. Targeted sequencing of retroperitoneal extra-organ myxoid liposarcoma demonstrated genetic heterogeneity. Our study was the first to describe mutations and polymorphic variants in genes, such as EGFR, PIK3CA, ALK, BRAF, ERBB2 / 3, ESR1, KIT, PDGFRA in myxoid liposarcoma.

Conclusion. This study demonstrated a wide range of molecular genetic rearrangements in retroperitoneal extra-organ myxoid liposarcoma. Synonymous mutations in the EGFR (Q787Q) and PDGFRA (P567P) genes were detected in all cases (100 %). Missense mutations in the ERBB2 gene (P1170A) and synonymous mutations in the ALK (G845G) and BRAF genes were identified in 75 % of cases. Missense mutation in the PIK3CA gene (I391M) was detected in 25 % of cases. The gene polymorphisms presented in this paper are most likely involved in the carcinogenesis of retroperitoneal myxoid liposarcoma. Further studies with larger patient groups and multivariate analysis of long-term treatment results are required. 

Effect of epidermal growth factor receptor gene polymorphisms on prognosis in glioma patients

Previous studies suggested that single nucleotide polymorphisms (SNPs) in epidermal growth factor receptor (EGFR) are associated with risk of glioma. However, the associations between these SNPs and glioma patient prognosis have not yet been fully investigated. Therefore, the present study was aimed to evaluate the effects of EGFR polymorphisms on the glioma patient prognosis. We retrospectively evaluated 269 glioma patients and investigated associations between EGFR SNPs and patient prognosis using Cox proportional hazard models and Kaplan-Meier curves. Univariate analysis revealed that age, gross-total resection and chemotherapy were associated with the prognosis of glioma patients (p < 0.05). In addition, four EGFR SNPs (rs11506105, rs3752651, rs1468727 and rs845552) correlated with overall survival (OS) (Log-rank p = 0.011, 0.020, 0.008, and 0.009, respectively) and progression-free survival PFS (Log-rank p = 0.026, 0.024, 0.019 and 0.009, respectively). Multivariate analysis indicated that the rs11506105 G/G genotype, the rs3752651 and rs1468727 C/C genotype and the rs845552 A/A genotype correlated inversely with OS and PFS. In addition, OS among patients with the rs730437 C/C genotype (p = 0.030) was significantly lower OS than among patients with A/A genotype. These data suggest that five EGFR SNPs (rs11506105, rs3752651, rs1468727, rs845552 and rs730437) correlated with glioma patient prognosis, and should be furthered validated in studies of ethnically diverse patients.

Evaluation of the EGFR polymorphism R497K in two cohorts of neoadjuvantly treated breast cancer patients

Pathological response of breast cancer to neoadjuvant chemotherapy (NAC) presents great variability, and new prognostic biomarkers are needed. Our aim was to evaluate the association of the epidermal growth factor receptor gene (EGFR) polymorphism R497K (rs2227983) with prognostic features and clinical outcomes of breast cancer, including the pathological response to NAC and the recurrence-free survival (RFS). Tumoral complete response (tCR) was defined by no remaining invasive cancer in the excised breast, whereas pathological complete response (pCR) was defined by no remaining invasive cancer both in the excised breast and lymph nodes. Two independent cohorts were analyzed: one from Brazil (INCA, n = 288) and one from The Netherlands (NKI-AVL, n = 255). In the INCA cohort, the variant (Lys-containing) genotypes were significantly associated with lower proportion of tCR (ORadj = 0.92; 95%CI = 0.85-0.99), whereas in the NKI-AVL cohort they were associated with tumor grade 3 (p = 0.035) and with triple-negative subtype (p = 0.032), but not with clinical outcomes. Such distinct prognostic associations may have arisen due to different neoadjuvant protocols (p < 0.001), or to lower age at diagnosis (p < 0.001) and higher proportion of tumor grade 3 (p = 0.018) at the NKI-AVL cohort. Moreover, NKI-AVL patients achieved better proportion of pCR (21.2% vs 8.3%, p < 0.001) and better RFS (HRadj = 0.48; 95% adjCI = 0.26-0.86) than patients from INCA. In conclusion, large scale studies comprehending different populations are needed to evaluate the impact of genome variants on breast cancer outcomes.

Correlations between EGFR gene polymorphisms and pleural metastasis of lung adenocarcinoma

Proliferation, growth, and differentiation of cells are strictly controlled by the signal system of epidermal growth factor receptor (EGFR). If any link of the EGFR signals system is interfered with or damaged, the proliferation, growth, and differentiation of cells would become uncontrolled. EGFR is overexpressed in a variety of malignant tumors, such as non-small-cell lung cancer, colorectal cancer and breast cancer. Results of the study have proved that EGFR overexpression is closely associated with mutations and variants of the EGFR genes, whose mutations and variants are associated with occurrence, metastasis, and prognosis of different types of tumors, including lung cancer. This study is aimed at investigating whether the polymorphisms of CA simple sequence repeat in intron 1 (CA-SSR1), -216G/T, and R497K in the EGFR are able to induce EGFR activation and whether overexpression is associated with pleural metastasis of lung adenocarcinoma. A total of 432 lung adenocarcinoma patients with pleural metastasis (metastasis group) and 424 patients with lung adenocarcinoma but without pleural metastasis (nonmetastasis group) were enrolled in this study. For all patients, the CA-SSR1 genotypes were determined by capillary electrophoresis, polymerase chain reaction amplification, and direct DNA sequencing, and the R497K and -216G/T genotypes were determined by polymerase chain reaction amplification and direct DNA sequencing. EGFR expression was evaluated by immunohistochemical staining in primary tumor tissues with different -216G/T, R497K, and CA-SSR1 genotypes. Our results showed significant differences between pleural metastasis and nonmetastasis groups in the genotype and allele distribution of -216G/T, R497K, and CA-SSR1 polymorphisms of the EGFR gene. The -216T allele, Arg allele, and shorter CA-SSR1 (<17) had significantly increased risks of pleural metastasis compared with the -216G allele, Lys allele, and longer CA-SSR1 (≥17), respectively. The expression of EGFR was higher in patients with genotypes of -216T/T or -216G/T, Arg/Arg or Arg/Lys, and shorter CA-SSR1 (<17) than that in patients with genotypes of -216G/G, Lys/Lys, and longer CA-SSR1 (≥17), respectively. These results indicate that -216G/T, R497K, and CA-SSR1 polymorphisms are associated with the risk of pleural metastasis of lung adenocarcinoma, which may be related to the overexpression of EGFR protein induced by -216G/T, R497K, and CA-SSR1 polymorphisms.

Novel therapeutics in metastatic colorectal cancer: molecular insights and pharmacogenomic implications

Although the survival of metastatic colorectal cancer (mCRC) patients has improved five-fold over the last century, CRC remains a significant global health burden. Impressive strides have been made in identifying new regimens, employing maintenance strategies to limit treatment toxicities, and combining multidisciplinary approaches to achieve cure in oligometastatic disease. Attempts at personalized integration of targeted agents have been limited by the ability to identify molecularly enriched patient populations most likely to benefit. In this review, we discuss novel therapeutics and regimens recently approved and in development for mCRC. In addition, we discuss using older agents in novel combination and maintenance strategies, and highlight evidence for implementing pharmacogenomic data and non-invasive monitoring into the personalized management of mCRC patients.

ErbB polymorphisms: insights and implications for response to targeted cancer therapeutics

Advances in high-throughput genomic-scanning have expanded the repertory of genetic variations in DNA sequences encoding ErbB tyrosine kinase receptors in humans, including single nucleotide polymorphisms (SNPs), polymorphic repetitive elements, microsatellite variations, small-scale insertions and deletions. The ErbB family members: EGFR, ErbB2, ErbB3, and ErbB4 receptors are established as drivers of many aspects of tumor initiation and progression to metastasis. This knowledge has provided rationales for the development of an arsenal of anti-ErbB therapeutics, ranging from small molecule kinase inhibitors to monoclonal antibodies. Anti-ErbB agents are becoming the cornerstone therapeutics for the management of cancers that overexpress hyperactive variants of ErbB receptors, in particular ErbB2-positive breast cancer and non-small cell lung carcinomas. However, their clinical benefit has been limited to a subset of patients due to a wide heterogeneity in drug response despite the expression of the ErbB targets, attributed to intrinsic (primary) and to acquired (secondary) resistance. Somatic mutations in ErbB tyrosine kinase domains have been extensively investigated in preclinical and clinical setting as determinants for either high sensitivity or resistance to anti-ErbB therapeutics. In contrast, only scant information is available on the impact of SNPs, which are widespread in genes encoding ErbB receptors, on receptor structure and activity, and their predictive values for drug susceptibility. This review aims to briefly update polymorphic variations in genes encoding ErbB receptors based on recent advances in deep sequencing technologies, and to address challenging issues for a better understanding of the functional impact of single versus combined SNPs in ErbB genes to receptor topology, receptor-drug interaction, and drug susceptibility. The potential of exploiting SNPs in the era of stratified targeted therapeutics is discussed.

EGF and EGFR genetic polymorphisms predict prognosis in locally advanced pharyngolaryngeal squamous cell carcinoma patients receiving postoperative concurrent chemoradiotherapy

Background

Epidermal growth factor (EGF) and its receptor (EGFR) are part of an important signaling pathway that is involved in the pathogenesis of squamous cell carcinoma of the head and neck (SCCHN). We hypothesized that EGF/EGFR genetic polymorphisms might have a prognostic impact on disease-free survival and overall survival (OS) in locally advanced SCCHN.

Materials and methods

The patient group included a consecutive cohort of 180 patients with locally advanced SCCHN who underwent postoperative concurrent chemoradiotherapy between 2002 and 2010. DNA from formalin-fixed, paraffin-embedded tumor tissues was genotyped for the single nucleotide polymorphism (SNP) of EGF A61G A>G, EGFR R521K G>A and G-216T. The log-rank test was applied to evaluate the impact of SNPs on the outcomes. Survival was estimated using the Kaplan–Meier statistical method.

Results

We demonstrated that EGF/EGFR SNPs might predict prognosis in patients with primary pharyngolaryngeal tumors, but not in those with oral cavity tumors. In pharyngolaryngeal tumor subgroup, EGF61 G/G genotype led to worse 5 year OS rate when compared to G/A or A/A genotypes (13.3% versus 34.3% versus 50.0%, P=0.017). The 5 year OS of patients with EGFR R521K G/G (11.1%) and G/A (15.9%) were lower than the A/A (62.5%) genotype (P=0.054). Patients carrying one or two unfavorable alleles had worse 5 year OS than those without unfavorable allele (not available versus 20% versus 71.4%, P=0.002). Multivariate analysis revealed that the highest risk of death was associated with the coexistence of two unfavorable genotypes (hazard ratio 25.7, 95% confidence interval =3.4–193.4; P=0.002).

Conclusion

In this study, we were able to demonstrate that the EGF A61G and EGFR R521K genetic polymorphisms might be important prognostic factors in patients with locally advanced primary pharyngolaryngeal squamous cell carcinoma who underwent postoperative concurrent chemoradiotherapy.

A Meta-Analysis on the Relations between EGFR R521K Polymorphism and Risk of Cancer

The EGFR R521K polymorphism has been shown to reduce the activity of EGFR; however, the association between EGFR R521K polymorphism and the risk of cancer remains inconclusive; therefore we performed a meta-analysis to evaluate the relationship between EGFR R521K polymorphism and susceptibility to cancer. Our results suggest that the EGFR R521K polymorphism is not associated with risk of cancer, but the different chemosensitivity to anticancer drugs may need further investigation.

Genetic variants of EGF and VEGF predict prognosis of patients with advanced esophageal squamous cell carcinoma

PURPOSE

To investigate the association between genetic polymorphisms of growth factor-related genes and prognosis in patients with advanced esophageal squamous cell carcinoma (ESCC).

PATIENTS AND METHODS

A total of 334 ESCC patients with advanced tumor stages (stages IIB, III and IV) were enrolled in the study. The genotypes of 14 candidate single nucleotide polymorphisms (SNPs) involved in growth factor-related functions were analyzed using iPLEX Gold technology from the genomic DNA of peripheral leukocytes, and were correlated with the clinical outcome of patients. Serum levels of growth factors were examined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The genetic polymorphisms of EGF:rs4444903, EGF:rs2237051 and VEGF:rs2010963 showed significant associations with overall survival (OS) of advanced ESCC patients (A/A+ A/G vs. GG, [HR = 0.77, 95% CI = 0.60-0.99, P = 0.039 for rs4444903; A/G+ G/G vs. A/A, [HR = 0.74, 95% CI = 0.58-0.95, P = 0.019 for rs2237051; G/G+G/C vs. C/C, [HR] inves = 0.69, 95% CI = 0.50-0.95, P = 0.023 for rs2010963). EGFR:rs2227983 and 3 SNPs of PIK3CA also showed borderline significant correlation with OS of advanced ESCC patients (P = 0.058 for rs2227983; P = 0.069, 0.091 and 0.067 for rs6443624, rs7651265 and rs7621329 of PIK3CA respectively). According to cumulative effect analysis of multiple SNPs, patients carrying 4 unfavorable genotypes exhibited more than a 3-fold increased risk of mortality. Finally, both EGF and VEGF expression levels significantly associated with patient mortality.

CONCLUSION

The genetic variants and expression levels of EGF and VEGF can serve as prognostic predictors in patients with advanced ESCC, and thus provide more information for optimizing personalized therapies for patients with ESCC.

Clinical importance of recently discovered gene variants in colon cancer recurrence and prognosis

SUMMARY 

Colorectal cancer survival has increased over the past few years, mainly due to the advances in the metastatic setting. Nonetheless, in the adjuvant scenario, minor improvements have been made, as the tumor's anatomopathological features remain to be most important factors for predicting the risk of recurrence and the prognosis. A deeper understanding of the molecular mechanisms involved in colorectal carcinogenesis, progression, invasion and metastasis development, have laid the groundwork for the search of genetic biomarkers that can help identify patients at a higher risk of recurrence. Common germline variants in genes within molecular pathways responsible for cancer development and progression have proven to influence the probability of relapse and the patient's prognosis. Here, we systematically review the relevance of genetic variants as prognostic biomarkers in colorectal carcinoma.

Sex disparities in the association of lung adenocarcinoma with colorectal cancer

Background: Most cancers share common risk factors. It might provide evidence of shared risk factors with cancers by investigating cross-country and cross-township comparisons.

Methods: The data were obtained from International Association of Cancer Registries/World Health Organization and the National Cancer Registration Program of Taiwan. Age standardized incidence rates were calculated among gastric cancer, colorectal cancer and lung adenocarcinoma in 19 countries from 1995 to 1998. The Pearson correlations were also compared among 3 types of cancers for both sexes.

Results: The incidence rates of gastric and colorectal cancer throughout different countries show male dominance with a male-to-female sex ratio of around 2 and 1.5, respectively. Significant cross-country correlations in colorectal cancer (r=0.918, p<0.001), gastric cancer (r=0.985, p<0.001) and lung adenocarcinoma (r=0.685, p=0.001) were observed between men and women. There was a significant international correlation between colorectal cancer and lung adenocarcinoma in men (r=0.526, p=0.021), but not in women. In cross-township comparisons of Taiwan, there were significant correlations in colorectal cancer (r=0.451, p<0.001), gastric cancer (r=0.486, p<0.001), and lung adenocarcinoma (r=0.217, p<0.001) between men and women. There were links of lung adenocarcinoma and gastric cancer (r=0.122, p=0.024) and colorectal cancer (r=0.128, p=0.018) in women, and lung adenocarcinoma and colorectal cancer in men (r=0.276, p<0.001).

Conclusions: There were associations between lung adenocarcinoma and colorectal cancer between and in both sexes in Taiwan, but not in cross-country comparisons. The results suggest that some factor, like genes, may be important as determinants for the association between lung adenocarcinoma and colorectal cancer.

Allele Frequencies of the Epidermal Growth Factor Receptors Polymorphism R521K in Colorectal Cancer Patients and Healthy Subjects Indicate a Risk-Reducing Effect of K521 in Syrian Population

Background:

Colorectal cancer contributes heavily to cancer morbidity and mortality worldwide. Numerous therapies are currently in use, including monoclonal antibodies against cellular components involved in tumorigenesis such as epidermal growth factor receptors (EGFRs). Studies showed the polymorphism [R521K] GàA in the EGFR gene to be involved in both colorectal cancer susceptibility and clinical response to therapeutics (e.g., Cetuximab).

Aim:

We aimed at uncovering allele frequencies of this polymorphism among Syrian colorectal cancer patients and healthy individuals.

Materials and Methods:

Forty-seven patients with colorectal cancer were included in a case-control study along with 48 healthy subjects, all native Syrians. Individuals were genotyped using PCR-Restriction Fragment Length Polymorphism (PCR-RFLP) and results were statistically analyzed to elucidate significant differences between the two groups.

Results:

Allele frequencies were 40.4% (G/G), 57.4% (G/A) and 2.1% (A/A) in colorectal cancer patients and 41.6% (G/G), 43.7% (G/A) and 14.5% (A/A) in healthy subjects. The A/A genotype was significantly lower in colorectal cancer patients than in the control group.

Conclusions:

Homozygosity for the A allele is linked to reducing the risk of developing colorectal cancer in Syrian patients. The lower prevalence of (A/A) locally may predict sub-optimal rates of clinical response to Cetuximab compared with populations with higher frequencies of the A allele. Larger scale investigations are needed for a stronger conclusion.

EGF receptor-targeted therapy in non-small-cell lung cancer: role of germline polymorphisms in outcome and toxicity

Conventional chemotherapeutic regimens have limited impact against most solid tumors and deal with significant toxicity. Over the last 10 years, novel anticancer treatments targeting specific molecules or genes involved in cancer progression have been developed to improve outcome and reduce side effects. In particular, the tyrosine kinase inhibitors gefitinib and erlotinib have been approved for the treatment of non-small-cell lung cancer. Their clinical activity has been related to different clinical and biological parameters, such as EGFR-activating mutations. However, not all clinical outcomes, including tolerability, are explained, and the identification/validation of novel biomarkers is a viable area of research. Germline polymorphisms can be easily assessed in blood samples, and candidate polymorphisms in EGFR and ABCG2 have been correlated with outcome and toxicity in non-small-cell lung cancer patients treated with gefitinib or erlotinib. However, differences in study population and design resulted in several controversial findings, while the prognostic versus predictive role of the polymorphisms still needs to be validated within larger prospective studies. More studies on the relationship of the genotype with drug pharmacokinetics and mechanism of action are also warranted. These future studies, as well as further development and application of novel technologies to decipher genetic alterations, might contribute to the validation of selected polymorphisms as molecular markers predictive of drug activity and help in the selection of tyrosine kinase inhibitors best suited to the individual patient.

EGFR signaling pathway and related-miRNAs in age-related diseases: the example of miR-221 and miR-222

Presently, neurodegenerative diseases and cancer are the most clinically problematic age-related diseases worldwide. Although being distinct disorders, their developments share common cellular mechanisms. Oncogenesis and neurodegeneration arise from the deregulation of signaling pathways, as a consequence of the resulting imbalance in cellular homeostasis. The epidermal growth factor receptor (EGFR) belongs to an important cellular signaling pathway, which regulates proliferation, differentiation, cell cycle and migration. As transcriptional targets of EGFR, the microRNAs-221/222 (miR-221/222) are important expression regulators. Dysfunctions in their networks are associated with cellular disruptions. The transcriptional activation of these microRNAs (miRNAs) seems to be involved in cell cycle, apoptosis, metastization, and in the acquisition of resistance to therapies. The up-regulation of miR-221/222 is associated with increased expression levels of matrix metalloproteinases (MMPs) and repression of cell cycle inhibitors, which are key molecules in oncogenesis and neurodegeneration processes. The interaction loop between proliferative signaling pathways and miRNA expression could reveal new targets for controlling the molecular behavior of age-related diseases.

EGFR pathway biomarkers in erlotinib-treated patients with advanced pancreatic cancer: translational results from the randomised, crossover phase 3 trial AIO-PK0104

Background:

We aimed to identify molecular epidermal growth factor receptor (EGFR) tissue biomarkers in pancreatic cancer (PC) patients treated with the anti-EGFR agent erlotinib within the phase 3 randomised AIO-PK0104 study.

Methods:

AIO-PK0104 was a multicenter trial comparing gemcitabine/erlotinib followed by capecitabine with capecitabine/erlotinib followed by gemcitabine in advanced PC; primary study end point was the time-to-treatment failure after first- and second-line therapy (TTF2). Translational analyses were performed for KRAS exon 2 mutations, EGFR expression, PTEN expression, the EGFR intron 1 and exon 13 R497K polymorphism (PM). Biomarker data were correlated with TTF, overall survival (OS) and skin rash.

Results:

Archival tumour tissue was available from 208 (74%) of the randomised patients. The KRAS mutations were found in 70% (121 out of 173) of patients and exclusively occurred in codon 12. The EGFR overexpression was detected in 89 out of 181 patients (49%) by immunohistochemistry (IHC), and 77 out of 166 patients (46%) had an EGFR gene amplification by fluorescence in-situ hybridisation (FISH); 30 out of 171 patients (18%) had a loss of PTEN expression, which was associated with an inferior TTF1 (first-line therapy; HR 0.61, P=0.02) and TTF2 (HR 0.66, P=0.04). The KRAS wild-type status was associated with improved OS (HR 1.68, P=0.005); no significant OS correlation was found for EGFR–IHC (HR 0.96), EGFR–FISH (HR 1.22), PTEN–IHC (HR 0.77), intron 1 (HR 0.91) or exon 13 R497K PM (HR 0.83). None of the six biomarkers correlated with the occurrence of skin rash.

Conclusion:

The KRAS wild-type was associated with an improved OS in erlotinib-treated PC patients in this phase 3 study; it remains to be defined whether this association is prognostic or predictive.

EGFR 3'UTR 774T>C polymorphism contributes to bladder cancer risk

Much evidence show that over-expression of epidermal growth factor receptor (EGFR) plays an important role in regulating carcinogenesis. Genetic variations in 3' untranslated region (3'UTR) of gene have been reported to affect gene expression by interfering with microRNAs (miRNAs), which are thought to function as either tumour suppressors or oncogenes by binding to their target mRNA. In this study, we investigated the association between the EGFR 3'UTR 774T>C polymorphism and bladder cancer risk. We used the TaqMan technology to genotype this genetic variant in a hospital-based case-control study of 908 bladder cancer patients and 1239 controls in a Chinese population. We found that the 774CC genotype was associated with a statistically significantly increased risk of bladder cancer [adjusted odds ratio = 1.29, 95% confidence interval = 1.05-1.58], compared with the 774TT/TC genotype, and this increased risk was more pronounced among subgroups of age > 65 years, non-smokers and patients' tumour invasive stage. Furthermore, luciferase assays in T24 cell showed that EGFR 3'UTR 774 T to C substitution could increase the expression of EGFR, which was consistent with the association study finding. Additionally, we also provide evidence that 774T>C polymorphism increasing EGFR expression was not regulated by hsa-miR-214 binding. These findings suggested that EGFR 3'UTR 774T>C polymorphism may contribute to susceptibility to bladder cancer.

EGFR and KRAS mutational analysis and their correlation to survival in pancreatic and periampullary cancer

OBJECTIVES

Pancreatic and periampullary cancers have a high incidence of activating KRAS mutations. The aim of this study was to determine the incidence of KRAS and EGFR mutations in pancreatic and periampullary cancers and their relationship with survival.

METHODS

One hundred patients undergoing pancreaticoduodenectomy or pancreatic biopsy for cancer were recruited. Samples of formalin-fixed paraffin-embedded or fresh pancreatic tissue were obtained. EGFR was analyzed by DNA sequencing of exons 18 to 21. KRAS was analyzed by pyrosequencing of codons 12, 13, and 61.

RESULTS

EGFR mutations were found in 2 (2.3%) of 88 assessable cases. One in exon 18 (c.1966C>T, p.Q710X) and 1 in exon 19 (c.2066A>G, p.E734G). A synonymous single-nucleotide polymorphism in exon 20 (c.2361G>A, p.Q787) was identified in 57 (67.8%) of 84 patients studied. Twenty-eight (41.2%) of 68 cases harbored a point mutation in KRAS codon 12 (26 cases) and codon 61 (2 cases). The overall median survival was 308 days (range, 7-2623 days). The presence of KRAS point mutations did not significantly alter median survival time (22.8 vs 28.1 months, P = 0.88).

CONCLUSIONS

EGFR somatic mutations are rare in pancreatobiliary malignancies. KRAS mutations are less common than previous reports and do not correlate with survival.

CIP2A overexpression is associated with c-Myc expression in colorectal cancer

BACKGROUND

To improve the prognostic evaluation of colorectal cancer requires new molecular markers. Cancerous inhibitor of protein phosphatase 2A (CIP2A) serves as an oncoprotein by targeting PP 2A-mediated inhibition of c-Myc. A prognostic role for CIP2A has been demonstrated in gastric, lung and tongue cancers.

RESULTS

CIP2A was overexpressed in 661 (87.9%) specimens. CIP2A overexpression was associated with tumor differentiation grade (p = 0.014), p53 immunopositivity (p = 0.042), EGFR immunopositivity (p = 0.007) and c-Myc nuclear immunopositivity (p = 0.018). In survival analysis, CIP2A failed to show any prognostic significance (p = 0.270, log-rank test).

METHODS

863 consecutive colorectal cancer patients treated at Helsinki University Central Hospital in 1983–2001 were collected with 752 scored successfully for CIP2A immunohistochemical expression from tumor tissue microarrays. Associations with clinicopathologic variables and molecular markers were explored by the chi-square test, and the Kaplan-Meier method served for survival analysis.

CONCLUSIONS

Overexpression of CIP2A in colorectal cancer patients may be an important step in colorectal carcinogenesis. Based on our findings, CIP2A shows no association with patient prognosis in colorectal cancer, but is associated with nuclear c-Myc.

Epidermal growth factor receptor R521K polymorphism shows favorable outcomes in KRAS wild-type colorectal cancer patients treated with cetuximab-based chemotherapy

The R521K polymorphism of epidermal growth factor receptor has attenuated affinity in ligand binding and proto-oncogene induction, which may affect the efficacy of cetuximab. We analyzed the effect of this polymorphism on the outcome of 112 patients with KRAS wild-type metastatic colorectal carcinoma treated with first-line cetuximab plus FOLFOX-4. The associations of this polymorphism with vascular endothelial growth factor (VEGF) expression and clinicopathologic characteristics were also examined. The results showed that the frequencies of the G/G, G/A, and A/A genotypes were 32.1% (n = 36), 42.9% (n = 48), and 25.0% (n = 28), respectively. A marked decrease in VEGF expression levels (66.7% vs 28.9%, P < 0.01) was observed in patients with 521A allele variants (Arg/Lys or Lys/Lys), which were associated with a decreased tumor size (55.6% vs 31.6%, P = 0.02), good histological differentiation (63.9% vs 85.5%, P = 0.01), decreased lymphovascular invasion (69.4% vs 39.5%, P < 0.01), and a higher response rate to cetuximab plus FOLFOX treatment (55.6% vs 78.9%, P = 0.01). In addition, this polymorphism was associated with a longer progression-free period (P = 0.001) and overall survival (P = 0.001). By multivariate analysis, this polymorphism was also identified as an independent prognostic factor. These data suggest that the R521K polymorphism of epidermal growth factor receptor, by reducing its activation and a consequential downregulation of its target genes, including VEGF, could be a key determinant of an increased response to cetuximab-based chemotherapy and a longer survival for KRAS wild-type colorectal carcinoma patients.

The status of EGFR CA SSR1 is a potential prognostic factor for patients with oral squamous cell carcinoma

The EGFR is an oncogene known to be involved in the development and progression of many cancers. It has been reported that the expression of EGFR and EGFR CA simple sequence repeat 1 (CA SSR1) repeat numbers in tumors can be useful prognostic factors in several cancer types. The objective of the present study was to analyze whether the EGFR polymorphism can be a useful prognostic factor in OSCC in the Taiwanese population. OSCC tissues were collected from 47 patients by surgical excision. The genotyping of EGFR were performed with the ABI Prism 3100 Genetic Analyzer. OSCC patients had a tendency toward an allelic imbalance of CA SSR1. The results also suggested that OSCC patients who were homozygous for CA SSR1 had a poorer prognosis than those who were heterozygous (P<0.001). Besides, patients with an allelic imbalance of CA SSR1 had significantly lower overall and disease free survival rates than those without, using the Kaplan-Meier method (P<0.001). This suggests that the status of CA SSR1 has the potential to be a useful prognosis factor in OSCC.

Epidermal growth factor receptor in pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer related death. The difficulty in detecting pancreatic cancer at an early stage, aggressiveness and the lack of effective therapy all contribute to the high mortality. Epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein, which is expressed in normal human tissues. It is a member of the tyrosine kinase family of growth factors receptors and is encoded by proto-oncogenes. Several studies have demonstrated that EGFR is over-expressed in pancreatic cancer. Over-expression correlates with more advanced disease, poor survival and the presence of metastases. Therefore, inhibition of the EGFR signaling pathway is an attractive therapeutic target. Although several combinations of EGFR inhibitors with chemotherapy demonstrate inhibition of tumor-induced angiogenesis, tumor cell apoptosis and regression in xenograft models, these benefits remain to be confirmed. Multimodality treatment incorporating EGFR-inhibition is emerging as a novel strategy in the treatment of pancreatic cancer.

Panitumumab: the evidence for its use in the treatment of metastatic colorectal cancer

Panitumumab is the first fully human monoclonal antibody to Epidermal Growth Factor Receptor (EGFR) to enter clinical trials for the treatment of solid tumors. The anti-tumor activity of panitumumab has been tested in vitro and in vivo, and inhibition of tumor growth has been observed in numerous cancer models, particularly lung, kidney and colorectal (CRC). Preclinical and clinical studies have established a role for panitumumab in metastatic colorectal cancer (mCRC) refractory to multiple chemotherapeutic regimens. Based on these encouraging findings, panitumumab was approved by the US Food and Drug Administration for the treatment of patients with epidermal growth factor receptor-expressing mCRC refractory to fluoropyrimidine-, oxaliplatin-, and/or irinotecan-containing chemotherapeutic regimens. The improvement in progression free survival (PFS) and response rate (RR) produced by panitumumab monotherapy was significantly greater in patients with non mutated (wild-type) K-RAS than in those with mutant K-RAS. Therefore implementing routine K-RAS screening and limiting the use of EGFR inhibitors to patients with wild-type K-RAS appears the better strategy for select only the patients who could benefit from the therapy with panitumumab and also may have the potential for cost savings. The purpose of this review was to evaluate the patient-related, disease-related and economic-related evidence for the use of panitumumab in the treatment of metastatic colorectal cancer in clinical practice.

Practical and molecular evaluation of colorectal cancer: new roles for the pathologist in the era of targeted therapy

CONTEXT

Colorectal cancer is the third most common cancer and the fourth most common cause of cancer death worldwide. Patient cases are discussed in multidisciplinary meetings to decide on the best management on an individual basis. Until recently, the main task of the pathologist in such teams was to provide clinically useful reports comprising staging of colorectal cancer in surgical specimens. The advent of total mesorectal excision and the application of anti-epidermal growth factor receptor (EGFR)-targeted therapies for selected patients with metastasized colorectal cancer have changed the role of the pathologist.

OBJECTIVES

To present the traditional role of the pathologist in the multidisciplinary team treating patients with colorectal cancer, to address the technique of total mesorectal excision and its implications for the evaluation of surgical specimens, to offer background information on the various EGFR-targeted therapies, and to review the currently investigated tissue biomarkers assumed to be predictive for efficacy of such therapies, with a focus on the role of the pathologist in determining the status of such biomarkers in individual tumors.

DATA SOURCES

This article is based on selected articles pertaining to biopsy evaluation of colorectal carcinoma and reviews of EGFR-targeted therapies for this cancer. All references are accessible via the PubMed database (US National Library of Medicine and the National Institutes of Health).

CONCLUSIONS

Pathologists play an increasingly important role in the diagnosis and management of colorectal cancer because of the advent of new surgical techniques and of targeted therapies. It is expected that this role will increase further in the near future.

Epidermal growth factor receptor polymorphisms and risk for toxicity in paediatric patients treated with gefitinib

PURPOSE

To investigate associations between germline genetic variations in the epidermal growth factor receptor (EGFR) and toxicity in paediatric patients treated with gefitinib.

PATIENTS AND METHODS

Gefitinib treatment and toxicity data from five paediatric clinical trials were combined. EGFR genotypes evaluated included -191C>A, -216G>T, Arg497Lys and intron 1 CA sequence repeat number. The genetic variations were evaluated for associations with grade one or greater rash or diarrhoea during the first course of treatment.

RESULTS

The analysis included 110 patients, 60 (55%) with grade one or greater rash and 47 (43%) with grade one or greater diarrhoea. Among patients with the -216 GG (n=51), GT (n=41) and TT (n=16) genotypes, grade one or greater rash occurred in 52.9%, 46.3% and 87.5% of patients (p=0.003, recessive model), respectively. Diarrhoea occurred in 27.5%, 58.5% and 43.8% of patients with respective GG, GT and TT genotypes (p=0.004, dominant model). The -191C>A, intron 1 CA repeat number and Arg497Lys genotypes were not significantly associated with either rash or diarrhoea. EGFR -216 and -191 polymorphisms were in linkage disequilibrium (D'=0.66, p=0.01). The haplotype (-191C, -216T) was associated with increased risk for rash (p=0.049), but was not more predictive of rash than the single -216 polymorphism.

CONCLUSION

These findings indicate that EGFR -216G>T genotype is a predictive marker for the development of skin rash and diarrhoea in paediatric patients treated with gefitinib. Continued investigation of relationships between germline EGFR polymorphisms and the efficacy of EGFR inhibitors in paediatric patients is warranted.

Mechanisms of resistance to anti-EGFR monoclonal antibody treatment in metastatic colorectal cancer

Metastatic colorectal cancer (mCRC) continues to be counted as a major health problem. The introduction of newer cytotoxics, irinotecan and oxaliplatin, has achieved a significant improvement in survival rates. Novel targeted therapies (bevacizumab, and cetuximab) in combination with most efficient chemotherapy regimens have pushed the median survival beyond the 2-year mark and increased the proportion of patients which could benefit from resection of metastatic lesions. In addition, several studies have proved that the CRC mutation profiles should influence patient selection or stratification in prospective trials. KRAS mutational status represents a paradigm for biomarker development in the era of molecular targeted therapies. The present article is an overview of the most important studies in the development of biomarkers for the optimization of anti-epidermal growth factor receptor (anti-EGFR) treatment in mCRC, beyond KRAS mutations, which is a work in progress. The aim will be to identify molecular markers that might be used to select patients with a higher probability of response to anti-EGFR monoclonal antibodies. Overall the accumulating evidence of the molecular biology of CRC has substantially changed the approach to mCRC treatment and has given clinicians more rational options for treating this illness.

Association of polymorphisms in AKT1 and EGFR with clinical outcome and toxicity in non-small cell lung cancer patients treated with gefitinib

EGFR mutations are strongly predictive of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor activity in non-small cell lung cancer (NSCLC), but resistance mechanisms are not completely understood. The interindividual variability in toxicity also points out to the need of novel pharmacogenetic markers to select patients before therapy. Therefore, we evaluated the associations between EGFR and AKT1 polymorphisms and outcome/toxicity in gefitinib-treated NSCLC patients. Polymorphic loci in EGFR, and AKT1, and EGFR and K-Ras mutations were assessed in DNA isolated from blood samples and/or paraffin-embedded tumor from 96 gefitinib-treated NSCLC patients. Univariate and multivariate analyses compared genetic variants with clinical efficacy and toxicity using Fisher's, log-rank test, and Cox's proportional hazards model. AKT1-SNP4 association with survival was also evaluated in 127 chemotherapy-treated/gefitinib-naive patients, whereas its relationship with AKT1 expression and gefitinib cytotoxicity was studied in 15 NSCLC cell lines. AKT1-SNP4 A/A genotype was associated with shorter time-to-progression (P = 0.04) and overall survival (P = 0.007). Multivariate analyses and comparison with the gefitinib-nontreated population underlined its predictive significance, whereas the in vitro studies showed the association of lower AKT1 mRNA levels with gefitinib resistance. In contrast, EGFR-activating mutations were significantly correlated with response, longer time-to-progression, and overall survival, whereas EGFR -191C/A (P < 0.001), -216 G/T (P < 0.01), and R497K (P = 0.02) polymorphisms were strongly associated with grade >1 diarrhea. AKT1-SNP4 A/A genotype seems to be a candidate biomarker of primary resistance, whereas EGFR -191C/A, -216G/T, and R497K polymorphisms are associated with diarrhea when using gefitinib in NSCLC patients, thus offering potential new tools for treatment optimization.

Prognostic effect of activated EGFR expression in human colon carcinomas: comparison with EGFR status

BACKGROUND

Evidence suggests that epidermal growth factor receptor (EGFR)-activation status may better predict the clinical behaviour of colon cancers than does EGFR expression. However, the prognostic effect of phospho-EGFR in primary colon cancer remains undefined.

METHODS

Phospho-EGFR (Tyr-1173) and EGFR expression were analysed by immunohistochemistry (IHC) in tissue microarrays of TNM stage II and III colon cancers from completed adjuvant therapy trials (n=388). Staining intensity was scored and correlated with clinicopathological variables, DNA mismatch repair (MMR) status, rates of cell proliferation (Ki-67), apoptosis (caspase-3), and patient survival.

RESULTS

Phospho-EGFR expression was detected in 157 of 388 (40%) tumours, whereas EGFR was found in 214 of 361 (59%). Although phospho-EGFR was unrelated to clinicopathological variables, strong EGFR intensity was associated with higher tumour stage (P=0.03). Tumours overexpressing EGFR (P=0.0002) or phospho-EGFR (P=0.015) showed increased Ki-67, but not caspase-3 expression. Phospho-EGFR was not prognostic. EGFR intensity was associated with worse disease-free survival (DFS) (hazard ratio (HR): 1.21 (1.03, 1.41); P=0.019) and overall survival (OS) (HR: 1.19 (1.02, 1.39); P=0.028). Tumours expressing both EGFR and phospho-EGFR had similar survival as EGFR alone. Stage and lymph node number were prognostic for DFS and OS, and histological grade for OS. EGFR was an independent predictor of DFS (P=0.042) after adjustment for stage, histological grade, age, and MMR status.

CONCLUSION

Phospho-EGFR and EGFR expression were associated with tumour cell hyperproliferation. Phospho-EGFR was not prognostic, whereas increased EGFR intensity was independently associated with poor DFS.

Biomarkers predicting clinical outcome of epidermal growth factor receptor-targeted therapy in metastatic colorectal cancer

The monoclonal antibodies panitumumab and cetuximab that target the epidermal growth factor receptor (EGFR) have expanded the range of treatment options for metastatic colorectal cancer. Initial evaluation of these agents as monotherapy in patients with EGFR-expressing chemotherapy-refractory tumors yielded response rates of approximately 10%. The realization that detection of positive EGFR expression by immunostaining does not reliably predict clinical outcome of EGFR-targeted treatment has led to an intense search for alternative predictive biomarkers. Oncogenic activation of signaling pathways downstream of the EGFR, such as mutation of KRAS, BRAF, or PIK3CA oncogenes, or inactivation of the PTEN tumor suppressor gene is central to the progression of colorectal cancer. Tumor KRAS mutations, which may be present in 35%-45% of patients with colorectal cancer, have emerged as an important predictive marker of resistance to panitumumab or cetuximab treatment. In addition, among colorectal tumors carrying wild-type KRAS, mutation of BRAF or PIK3CA or loss of PTEN expression may be associated with resistance to EGFR-targeted monoclonal antibody treatment, although these additional biomarkers require further validation before incorporation into clinical practice. Additional knowledge of the molecular basis for sensitivity or resistance to EGFR-targeted monoclonal antibodies will allow the development of new treatment algorithms to identify patients who are most likely to respond to treatment and could also provide rationale for combining therapies to overcome primary resistance. The use of KRAS mutations as a selection biomarker for anti-EGFR monoclonal antibody (eg, panitumumab or cetuximab) treatment is the first major step toward individualized treatment for patients with metastatic colorectal cancer.

Genetic polymorphisms in the EGFR (R521K) and estrogen receptor (T594T) genes, EGFR and ErbB-2 protein expression, and breast cancer risk in Tunisia

We evaluated the association of epidermal growth factor receptor (EGFR) 142285G>A (R521K) and estrogen receptor alpha (ESR1) 2014G>A (T594T) single nucleotide polymorphisms with breast cancer risk and prognosis in Tunisian patients. EGFR 142285G>A and ESR1 2014G>A were genotyped in a sample of 148 Tunisian breast cancer patients and 303 controls using PCR-RFLP method. Immunohistochemitsry was used to evaluate the expression levels of EGFR, HER2, ESR1, progesterone receptor and BCL2 in tumors. We found no evidence for an association between EGFR R521K polymorphism and breast cancer risk. However, we found that the homozygous GG (Arg) genotype was more prevalent in patients with lymph node metastasis (P = .03) and high grade tumors (P = .011). The ESR1 2014G allele showed significant association with breast cancer risk (P = .025). The GG genotype was associated with HER2 overexpression and this association withstood univariate and multivariate analyses (P = .009; P = .021, resp.). These data suggest that the R521K might be a prognostic factor, because it correlates with both tumor grade and nodule status. The higher expression of HER2 in ESR1 T594T GG patients suggests the possibility that ESR1 gene polymorphisms accompanied by HER2 expression might influence the pathogenesis of breast cancers.

Pharmacogenetics in chemotherapy of colorectal cancer

Although in recent years, chemotherapeutic options for colorectal carcinoma have expanded, overall response rates are still too low, with high rates of toxicity. Pharmacogenetics aim at predicting both treatment response and adverse effects in individual patients. This review describes the current knowledge of pharmacogenetic markers in the systemic treatment of colorectal cancer. UGT1A1*28 leads to reduced conjugation of SN-38, the active metabolite of irinotecan, resulting in an increased rate of adverse effects, especially neutropenia. To a lesser extent, increased 5-FU toxicity is predicted by DPYD*2A. A variable number of tandem repeats polymorphism in the thymidylate synthase enhancer region, in combination with a single nucleotide polymorphism C>G, may predict poorer response to 5-FU. Efficacy of oxaliplatin is influenced by polymorphisms in components of DNA repair systems, such as ERCC1 and XRCC1. Polymorphic changes in the endothelial growth factor receptor probably predict cetuximab efficacy. Furthermore, the antibody-depended cell-mediated cytotoxic effect of cetuximab may be reduced by polymorphisms in the immunoglobin G fragment C receptors. Bevacizumab efficacy is suspected to be influenced by polymorphisms in the VEGF gene and the hypoxia inducible factor 1alpha gene. Although the interpretation of pharmacogenetic studies is complicated, results imply a promising way of pretreatment prediction of chemotherapy efficacy and toxicity.

Epidermal growth factor receptor gene polymorphisms, R497K, but not (CA)n repeat, is associated with dilated cardiomyopathy

BACKGROUND

Epidermal growth factor receptor (EGFR) has been recently implicated in pathological tissue remodelling and sustained remodelling processes can lead to pathological outcomes, such as cardiac hypertrophy in heart failure. Dilated cardiomyopathy (DCM) is the most common form of heart muscle disease, comprising 60% of the cases of identified cardiomyopathy. This study aimed to evaluate the association between the EGFR gene polymorphisms and DCM in a Chinese population.

METHODS

Genomic DNA was extracted from whole blood samples in 163 DCM patients and 185 control subjects. EGFR R497K (Arg497Lys) and (CA)n polymorphisms were genotyped, and the difference of their allele and genotype frequencies distribution between DCM patients and controls were analyzed.

RESULTS

No significant difference was observed in the frequency distribution of genotype and allele in (CA)n repeat between DCM patients and control subjects. The frequency of Lys allele in DCM patients was significantly higher than that in controls (64.4% and 53.8%, in DCM patients and controls, respectively p = 0.005, OR = 1.556, 95% CI = 1.146-2.111). The frequency for Lys/Lys genotype was significantly overrepresented in DCM patients (p = 0.020, OR = 2.105, 95% CI = 1.134-3.905, for Lys/Lys vs. Arg/Arg).

CONCLUSION

This study suggests that the R497K polymorphism may be associated with DCM in a Chinese population.

The importance of KRAS mutations and EGF61A>G polymorphism to the effect of cetuximab and irinotecan in metastatic colorectal cancer

BACKGROUND

The effect of anti-epidermal growth factor receptor (EGFR) antibodies (mAb) in metastatic colorectal cancer seems limited to KRAS wild-type (wt) tumours, but still a major fraction of KRASwt patients are nonresponders and supplementary selection criteria are needed. We investigated methodological aspects of KRAS testing and the predictive and prognostic value of KRAS status combined with three EGFR-related gene polymorphisms [single-nucleotide polymorphisms (SNPs)] in patients treated with cetuximab and irinotecan.

PATIENTS AND METHODS

The study included 71 patients referred to third-line cetuximab-irinotecan. Blood samples were analysed for SNPs. KRAS analysis was carried out by sequencing analysis and quantitative PCR (DxS kit) in primary tumour and distant metastases.

RESULTS

There was a clear correlation between KRAS status in primary tumours and metastasis. The DxS kit presented the highest sensitivity. Response was confined to KRASwt patients (40% response rate versus 0%, P < 0.1(-3)), which translated into a significant difference in PFS. The EGF61A>G polymorphism showed relation to clinical outcome. A combined biomarker analysis showed a 19% progression rate in KRASwt-EGF61 homozygote patients and 60% in the EGF61A/G patients (P = 0.006) and a significant increase in overall survival (17.1 versus 5.9 months, log-rank, P = 0.002).

CONCLUSION

The combined biomarker analysis maybe an attractive approach to selection of patients for third-line treatment including anti-EGFR mAbs.

Impact of EGFR gene polymorphisms on anticancer drug cytotoxicity in vitro

BACKGROUND AND OBJECTIVE

The epidermal growth factor receptor (EGFR) plays a major role in cell proliferation of epithelial tissues, and its alterations frequently contribute to oncogenesis. Several common polymorphisms of the EGFR gene have been described, at the level of both coding and regulatory sequences. Some of these polymorphisms are associated with alterations of EGFR expression and/or activity and may have an impact on the activity of anticancer agents. This study aims to analyze the relationships between specific EGFR functional polymorphisms and anticancer drug activity.

METHOD

We investigated, in the panel of 60 human tumor cell lines established by the National Cancer Institute (NCI-60), whether the EGFR polymorphisms -216G>T, -191C>A, Arg521Lys (R521K), Val592Ala (V592A), and Cys624Phe (C624F), and the intron 1 (CA)n repeat were associated with EGFR gene expression and the in vitro cytotoxicity of anticancer agents using data extracted from the NCI database. We also looked for mutations of exons 18-21, known to enhance the activity of tyrosine kinase inhibitors, and the deletion of exons 2-7, associated to the oncogenesis of glioblastomas.

RESULTS

In the NCI-60 cell lines, only two mutations were observed, both in exon 19, in a leukemia and melanoma cell line. These mutations have not been described previously in clinical samples and their functional role is uncertain. The allele frequencies of the -216G>T, -191C>A, and R521K single nucleotide polymorphisms (SNPs) in the NCI-60 panel were 33%, 8.5%, and 27%, respectively; the V592A and C624F SNPs were not found in any NCI-60 cell line. The intron 1 CA repeat was highly variable in the cell lines; 32 cell lines having a total number of repeats below 35, and 27 having a total number of repeats above 35. The heterozygous and variant homozygous cell lines for the -216G>T SNP presented a significantly higher expression of the EGFR gene than the homozygous wild-type lines. In contrast, there was no association between the -191C>A or R521K SNPs and EGFR gene expression. No association could be detected between the number of CA repeats in intron 1 and the expression of EGFR. The cell lines having at least one variant T allele at the -216G>T SNP were more sensitive to erlotinib and less sensitive to geldanamycin, topoisomerase I and II inhibitors, and alkylating agents than those without a variant allele. No relationship was detected between anticancer drug sensitivity and the -191C>A SNP. The R521K SNP was associated to lower sensitivity to alkylating agents. The number of CA repeats was associated with significant differences in anticancer drug activity: a high total number of CA repeats (>35 per diploid genome) was associated to increased sensitivity to alkylating agents and topoisomerase I and II inhibitors.

DISCUSSION

We provide evidence in this work that EGFR polymorphisms are associated with significant differences in the in vitro cytotoxicity of several types of DNA-interfering agents. Studies attempting a clinical validation of these clues are warranted.

EGFR R497K polymorphism is a favorable prognostic factor for advanced lung cancer

INTRODUCTION

It has been reported that the R497K polymorphism of the epidermal growth factor receptor (EGFR) gene has attenuated functions in ligand binding, tyrosine kinase activation, and growth stimulation. On other hand, EGFR gene mutations at kinase domain in non-small cell lung cancer (NSCLC) have been examined for their ability to predict sensitivity to gefitinib or erlotinib.

MATERIALS AND METHODS

We investigated the EGFR mutations and/or R497K polymorphism statuses in 225 surgically treated NSCLC cases. 192 adenocarcinoma cases were included. The presence or absence of EGFR polymorphism of exon 13 was analyzed by PCR-RFLP method.

RESULTS

EGFR mutations at kinase domain were found from 95 of 225 lung cancer patients. In 86.2% of patients, homo- or heterozygous Lys497 allele was present. No correlation existed between R497K EGFR genotype and clinico-pathological features, such as gender, smoking status, and pathological subtypes.

CONCLUSIONS

EGFR mutation status was not correlated with R497KEGFR genotype of lung cancers. In node-negative patients, R497KEGFR genotype was not correlated with disease outcome. In node-positive patients, however, R497K EGFR was significantly associated with better overall survival. This association was attributable to neo-adjuvant or adjuvant chemotherapy. In 46 total gefitinib treated NSCLC patients, the prognosis was not different between the EGFR wild type (GG) patients and AG+AA patients. R497KEGFR polymorphism might be associated with favorable prognosis of advanced lung cancers and correlated with chemosensitivity.

R497K polymorphism in epidermal growth factor receptor gene is associated with the risk of acute coronary syndrome

Background

Previous studies suggested that genetic polymorphisms in the epidermal growth factor receptor (EGFR) gene had been implicated in the susceptibility to some tumors and inflammatory diseases. EGFR has been recently implicated in vascular pathophysiological processes associated with excessive remodeling and atherosclerosis. Acute coronary syndrome (ACS) is a clinical manifestation of preceding atherosclerosis. Our purpose was to investigate the association of the EGFR polymorphism with the risk of ACS. In this context, we analyzed the HER-1 R497K and EGFR intron 1 (CA)_n repeat polymorphisms in 191 patients with ACS and 210 age- and sex-matched controls in a Chinese population, using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) strategy and direct sequencing.

Results

There were significant differences in the genotype and allele distribution of R497K polymorphism of the EGFR gene between cases and controls. The Lys allele had a significantly increased risk of ACS compared with the Arg allele (adjusted OR = 1.49, 95% CI: 1.12–1.98, adjusted P = 0.006). However, no significant relationship between the number of (CA)_n repeats of EGFR intron 1 (both alleles < 20 or any allele ≥ 20) and the risk of ACS was observed (adjusted OR = 0.97, 95% CI: 0.58–1.64, adjusted P = 0.911). Considering these two polymorphisms together, there was no statistically significant difference between the two groups.

Conclusion

R497K polymorphism of the EGFR gene is significantly associated with the risk of ACS. Our data suggests that R497K polymorphism may be used as a genetic susceptibility marker of the ACS.

A polymorphism of EGFR extracellular domain is associated with progression free-survival in metastatic colorectal cancer patients receiving cetuximab-based treatment

Background

Cetuximab, a monoclonal antibody targeting Epidermal Growth Factor Receptor (EGFR), is currently used in metastatic colorectal cancer (mCRC), but predictive factors for therapeutic response are lacking. Mutational status of KRAS and EGFR, and EGFR copy number are potential determinants of cetuximab activity.

Methods

We analyzed tumor tissues from 32 EGFR-positive mCRC patients receiving cetuximab/irinotecan combination and evaluable for treatment response. EGFR copy number was quantified by fluorescence in situ hybridization (FISH). KRAS exon 1 and EGFR exons coding for extracellular regions were sequenced.

Results

Nine patients experienced an objective response (partial response) and 23 were considered as nonresponders (12 with stable disease and 11 with progressive disease). There was no EGFR amplification found, but high polysomy was noted in 2 patients, both of which were cetuximab responders. No EGFR mutations were found but a variant of exon 13 (R521K) was observed in 12 patients, 11 of which achieved objective response or stable disease. Progression-free and overall survivals were significantly better in patients with this EGFR exon 13 variant. KRAS mutations were found in 14 cases. While there was a trend for an increased KRAS mutation frequency in nonresponder patients (12 mutations out of 23, 52%) as compared to responder patients (2 out of 9, 22%), authentic tumor response or long-term disease stabilization was found in KRAS mutated patients.

Conclusion

This preliminary study suggests that: an increase in EGFR copy number may be associated with cetuximab response but is a rare event in CRC, KRAS mutations are associated with low response rate but do not preclude any cetuximab-based combination efficacy and EGFR exon 13 variant (R521K) may predict for cetuximab benefit.

EGF-receptor targeting with monoclonal antibodies in colorectal carcinomas: rationale for a pharmacogenomic approach

Monoclonal antibodies directed against the EGF-receptor (EGFR) have recently been approved for the treatment of metastatic colorectal cancer (CRC) patients with EGFR-positive tumors at immunohistochemistry (IHC). Surprisingly, data demonstrate a lack of correlation between the tumor’s EGFR expression at IHC and outcome. Indeed, as pointed out from small experiences, patients with EGFR-IHC-negative metastatic CRC have the same chance as EGFR-IHC-positive patients to benefit from an anti-EGFR monoclonal antibody, underlying the importance of different, more reliable, selection criteria. In particular, the identification of such predictive factors is important as these agents are expensive, have side effects and are really only effective in a minority of patients. Several potential clinical and biological predictive markers of activity and/or efficacy for such agents have been evaluated in retrospective series with promising results. Moving from clinical data suggesting that there could be a subpopulation of CRC patients that are more liable to benefit from anti-EGFR monoclonal antibodies, here we review major studies on determinants of outcome in this field.