The prognostic values of EGFR expression and KRAS mutation in patients with synchronous or metachronous metastatic colorectal cancer

Metachronous colorectal cancer metastasis: Who, what, when and what to do about it

Metachronous colorectal cancer (CRC) metastasis occurs due to micrometastatic disease, in up to 23% of patients who have undergone curative-intent treatment. Metachronous metastasis tends to occur within 2 years of initial treatment. Diagnosis relies on posttreatment surveillance strategies. Care for patients with metachronous CRC metastasis is complex and requires careful multidisciplinary consideration. Those with isolated and technically resectable diseases are recommended to undergo metastasectomy with adjunct chemotherapy, however, survival, even after curative-intent resection, is poor.

HER-3 surface expression increases in advanced colorectal cancer representing a potential therapeutic target

HER-3 (also known as ErbB-3) is a human epidermal growth factor receptor tyrosine kinases family member, and its expression in CRC (colorectal cancer) tissues was previously associated with poor prognosis. In this study, HER-3 expression was analyzed by immunohistochemistry in two cohorts of early and advanced metastatic CRC patients. The first cohort included 180 patients diagnosed with CRC in absence of lymph nodes or distant metastases (Stage I and Stage II), while the second was obtained from 53 advanced metastatic CRC patients who developed synchronous (SM) and metachronous (MM) liver metastases. In the first early-stage CRC cohort, 86 out of 180 (47.8%) tumors showed membranous expression of HER-3, with a mean percentage of positive tumor cells of 25.7%; conversely, in advanced metastatic CRC primary tumors, HER-3 was detected in all specimens, with a mean percentage of positive tumor cells of 76.1%. Kaplan-Meier curves showed that in the advanced metastatic CRC group, patients with HER-3high tumors had a significantly lower Cancer-Specific Survival (CSS) rate compared to patients with HER-3low tumors (p = 0.021). Importantly, this worse CSS rate was observed only in the MM subgroup of patients with HER-3high tumors (p = 0.002). Multivariate analysis confirmed that high HER-3 expression represents a significant and strong risk factor for death in patients developing MM liver metastases (Hazard Ratio = 64.9; 95% Confidence Interval, 4.7-886.6; p = 0.002). In addition, using a specific anti-HER-3 antibody-drug conjugate, named EV20/MMAF, we showed that HER-3 + CRC cells can be efficiently targeted in vitro and in vivo. Overall, this study confirms that surface HER-3 is highly expressed in CRC and reveals that HER-3 expression increases in metastatic CRC patients compared to early stage. Importantly, the results suggest that HER-3 has a prognostic and therapeutic value in patients developing MM liver metastases.

Which patients are prone to suffer liver metastasis? A review of risk factors of metachronous liver metastasis of colorectal cancer

Background

In recent years, with the increasing incidence of colorectal cancer (CRC) and its high fatality rate, CRC has seized the attention of the world. And liver metastasis, as the main cause of death of CRC, has become the leading cause of treatment failure in CRC, especially metachronous liver metastasis, have caused patients who underwent bowel resection to experience multiple tortures.

Main body

Metachronous liver metastasis has severely affected the quality of life and prognosis of patients. Therefore, in this review, we discuss risk factors for metachronous liver metastasis of CRC, which is the premise for effective intervention for CRC patients who suffer metachronous liver metastasis after undergoing surgery, as well as the signaling pathways associated with CRC.

Conclusion

The occurrence of metachronous liver metastasis is closely related to histology-based prognostic biomarkers, serum-based biomarkers, tumor microenvironment, pre-metastatic niche, liquid biopsy and tissue-based biomarkers. Further research is required to explore the risk factors associated with liver metastasis of CRC.

Gut microbiota composition in chemotherapy and targeted therapy of patients with metastatic colorectal cancer

Studies have reported the effects of the gut microbiota on colorectal cancer (CRC) chemotherapy, but few studies have investigated the association between gut microbiota and targeted therapy. This study investigated the role of the gut microbiota in the treatment outcomes of patients with metastatic CRC (mCRC). We enrolled 110 patients with mCRC and treated them with standard cancer therapy. Stool samples were collected before administering a combination of chemotherapy and targeted therapy. Patients who had a progressive disease (PD) or partial response (PR) for at least 12 cycles of therapy were included in the study. We further divided these patients into anti-epidermal growth factor receptor (cetuximab) and anti-vascular endothelial growth factor (bevacizumab) subgroups. The gut microbiota of the PR group and bevacizumab-PR subgroup exhibited significantly higher α-diversity. The β-diversity of bacterial species significantly differed between the bevacizumab-PR and bevacizumab-PD groups (P = 0.029). Klebsiella quasipneumoniae exhibited the greatest fold change in abundance in the PD group than in the PR group. Lactobacillus and Bifidobacterium species exhibited higher abundance in the PD group. The abundance of Fusobacterium nucleatum was approximately 32 times higher in the PD group than in the PR group. A higher gut microbiota diversity was associated with more favorable treatment outcomes in the patients with mCRC. Bacterial species analysis of stool samples yielded heterogenous results. K. quasipneumoniae exhibited the greatest fold change in abundance among all bacterial species in the PD group. This result warrants further investigation especially in a Taiwanese population.

Monoclonal antibodies and chimeric antigen receptor (CAR) T cells in the treatment of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer deaths worldwide. Besides common therapeutic approaches, such as surgery, chemotherapy, and radiotherapy, novel therapeutic approaches, including immunotherapy, have been an advent in CRC treatment. The immunotherapy approaches try to elicit patients` immune responses against tumor cells to eradicate the tumor. Monoclonal antibodies (mAbs) and chimeric antigen receptor (CAR) T cells are two branches of cancer immunotherapy. MAbs demonstrate the great ability to completely recognize cancer cell-surface receptors and blockade proliferative or inhibitory pathways. On the other hand, T cell activation by genetically engineered CAR receptor via the TCR/CD3 and costimulatory domains can induce potent immune responses against specific tumor-associated antigens (TAAs). Both of these approaches have beneficial anti-tumor effects on CRC. Herein, we review the different mAbs against various pathways and their applications in clinical trials, the different types of CAR-T cells, various specific CAR-T cells against TAAs, and their clinical use in CRC treatment.

Nanomedicine of tyrosine kinase inhibitors

Recent progress in nanomedicine and targeted therapy brings new breeze into the field of therapeutic applications of tyrosine kinase inhibitors (TKIs). These drugs are known for many side effects due to non-targeted mechanism of action that negatively impact quality of patients' lives or that are responsible for failure of the drugs in clinical trials. Some nanocarrier properties provide improvement of drug efficacy, reduce the incidence of adverse events, enhance drug bioavailability, helps to overcome the blood-brain barrier, increase drug stability or allow for specific delivery of TKIs to the diseased cells. Moreover, nanotechnology can bring new perspectives into combination therapy, which can be highly efficient in connection with TKIs. Lastly, nanotechnology in combination with TKIs can be utilized in the field of theranostics, i.e. for simultaneous therapeutic and diagnostic purposes. The review provides a comprehensive overview of advantages and future prospects of conjunction of nanotransporters with TKIs as a highly promising approach to anticancer therapy.

Prognostic Biomarkers in Early-stage Gastric Adenocarcinoma Treated With Adjuvant Chemoradiotherapy

BACKGROUND/AIM

Early-stage gastric cancer has a high risk of recurrence, despite trimodality therapy with surgery, chemotherapy and radiation. To improve patient selection for adjuvant chemoradiotherapy, we evaluated the prognostic significance of immunohistochemical and genetic biomarkers in patients with resected gastric adenocarcinoma.

PATIENTS AND METHODS

Tumors from 119 patients were subjected to immunohistochemistry for 12 protein biomarkers, as well as next-generation sequencing. Clinical and biomarker data were available for 91 patients.

RESULTS

EBV-positive tumors and tumors with mutations had higher intratumoral CD8 tumor-infiltrating lymphocyte density (p=0.009 and p=0.017, respectively). PIK3CA mutations were correlated with VEGFA overexpression (p=0.042), while KRAS mutations and HER2 expression were mutually exclusive (p=0.036). PTEN expression univariately confirmed longer overall survival (HR=0.27; p=0.046), while there was a trend between the presence of KRAS mutations and inferior disease-free and overall survival.

CONCLUSION

PTEN protein expression and KRAS mutations may predict disease outcome in early-stage gastric cancer. These results need to be further validated in larger cohorts.

Prognostic Value of EGFR Expression for Patients With Stage III Colorectal Cancer Receiving Fluoropyrimidine Metronomic Maintenance Therapy After Radical Resection and Adjuvant Oxaliplatin-Based Chemotherapy

This study evaluated the survival effects of metronomic maintenance therapy with oral fluoropyrimidine in patients with stage III colorectal cancer (CRC) according to epidermal growth factor receptor (EGFR) expression. We enrolled 197 patients with stage III CRC who had undergone radical resection and FOLFOX regimen adjuvant chemotherapy. The clinicopathological features and effects of metronomic maintenance therapy with oral capecitabine (daily dose of 850 mg/m², twice daily, on days 1–14 every 3 weeks for 6 months) on survival according to treatment group and EGFR expression were analyzed. By conducting an in vitro cell line study and in vivo study through knockout of the EGFR gene, we analyzed the capacities of cell proliferation and migration. Relapse and survival were significantly more common in the FOLFOX group. Metronomic maintenance therapy was a significantly independent associated factor of relapse and survival as well as a prognostic factor of disease-free survival and overall survival. Significant intergroup differences in survival were only observed in patients with positive EGFR expression. Thus, our findings suggest EGFR expression is a prognostic factor in patients with stage III CRC receiving metronomic maintenance therapy. Analysis of EGFR expression in these patients helps identify potential candidates who may receive the optimal survival benefit from metronomic maintenance therapy.

Effect of KRAS and NRAS mutations on the prognosis of patients with synchronous metastatic colorectal cancer presenting with liver-only and lung-only metastases

It has been reported that 20–25% of patients with colorectal cancer (CRC) have metastases at the time of diagnosis. Liver and lung are the most common metastatic sites. The aim of the present study was to investigate the association of KRAS and NRAS mutations with clinicopathological features and prognosis of patients with initial liver-metastasis only (LiM-only) or lung-metastasis only (LuM-only) metastatic CRC (mCRC). Overall, 166 patients with CRC with initial LiM-only (n=124) and LuM-only (n=42) were retrospectively analyzed from January 2014 to December 2017. The median follow-up time was 19.2 months (1.0–57.1 months). Patient characteristics at diagnosis were collected. Genomic DNA was isolated from frozen primary CRC tissues for targeting KRAS and NRAS. Patients with LuM-only were significantly older compared with those with LiM-only (65.5 vs. 61.5 years; P=0.05). There was no significant differences between the LiM-only and LuM-only groups in terms of sex, location of the primary tumor, serum carcinoembryonic antigen level, histological grade and RAS mutation status. KRAS mutations were detected in 43 (41.0%) patients with LiM-only and 13 (35.1%) patients with LuM-only. The overall survival time (OS) of LuM-only was more favorable compared with that of patients with LiM-only (44.5 vs. 24.7 months); however, there was no significant difference (P=0.095). The progression-free survival (PFS) and OS in the RAS wild-type group were significantly improved compared with the RAS mutant cohorts (P=0.004 and P=0.031, respectively) in the LiM-only group. In patients with stage IV CRC, those with synchronous LiM-only mCRC had a higher incidence of metastasis but a less favorable PFS and OS compared with patients with LuM-only. RAS mutation status exhibited a significant association with the survival outcome in patients with LiM-only mCRC.

Regorafenib suppresses epidermal growth factor receptor signaling-modulated progression of colorectal cancer

Active epidermal growth factor receptors (EGFR) signaling mediates the progression of colorectal cancer (CRC) through activation of downstream kinases and transcription factors. The increased expression of EGFR was associated with worse prognosis in patients with metastatic CRC (mCRC). Regorafenib, the oral kinase inhibitor approved for the treatment of mCRC, has been shown to reduce activation of downstream kinases of EGFR signal pathway in hepatocellular carcinoma and osteosarcoma. However, whether EGFR inactivation was participates in regorafenib-inhibited progression of CRC still remaining ambiguous. The major purpose of present study was to verify effect of regorafenib on EGFR signaling-mediated progression of CRC. Here, we investigated the effect of regorafenib or erlotinib (EGFR inhibitor) on tumor cell growth, invasion ability, apoptotic, and EGFR signal transduction in CRC in vitro and in vivo. Our results indicated regorafenib reduced EGF-induced EGFR and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity. Both regorafenib and erlotinib significantly reduced cell invasion ability, activation of protein kinase C-δ (PKCδ), protein kinase B (AKT), extracellular signal-regulated kinases (ERK), and NF-κB. Regorafenib can trigger the inhibition of tumor cell growth and the induction of apoptosis through extrinsic/intrinsic apoptosis pathways. In addition, the expression of NF-κB-mediated proteins involved in tumor progression was also suppressed by regorafenib treatment. Taken together, regorafenib acts as a inhibitor of EGFR signaling that attenuated the activation of EGFR and EGFR related downstream signaling cascades in CRC. Our results suggested that the suppression of EGFR signaling was associated with regorafenib-inhibited progression of CRC.

Application of trastuzumab emtansine in HER-2-positive and KRAS/BRAF-mutated colon cancer cells

BACKGROUND

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate (ADC) for the treatment of human epidermal growth factor receptor 2 (HER-2)-positive breast cancer. T-DM1 is based on the trastuzumab antibody and delivers a toxic agent into breast cancer cells through endocytic mechanism. This study evaluated whether T-DM1 can be used in HER-2-positive colon cancer cells which harbour KRAS/ BRAF mutation with limited treatment.

MATERIALS AND METHODS

LS174T and HT-29 which are KRAS and BRAF mutant HER-2-positive colon cancer cells were used in this study. Cells were first treated with T-DM1; cetuximab and trastuzumab were applied for comparison, the effect of drug sensitivity was determined. Cells were then transfected with plasmid to overexpress HER-2 or the endocytic protein, caveolin-1 or furthermore pretreated with metformin to examine the effect of T-DM1 efficacy. Finally, a xenograft mouse model was used to evaluate the drug efficacy in vivo.

RESULTS

The results showed that T-DM1 had better inhibitory effect than cetuximab and trastuzumab on LS174T and HT-29 cells. HER-2 or caveolin-1 overexpression with plasmid in the cells to increase T-DM1 recognition or internalization can increase the sensitivity to T-DM1. When cells were pretreated with metformin, caveolin-1 expression was induced and promoted T-DM1 uptake and enhanced cell toxicity. In xenograft mouse model, combined treatment of T-DM1 and metformin had apparent inhibitory effect on subcutaneous tumour growth.

CONCLUSION

The results of this study suggested that T-DM1 has potential in the treatment of HER-2-positive colon cancer cells, and application of metformin has therapeutic benefits during T-DM1 treatment.

Epidermal growth factor receptor (EGFR) involvement in epithelial-derived cancers and its current antibody-based immunotherapies

The epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein that is part of the family of tyrosine kinase receptors. The binding of EGFR to its cognate ligands leads to its autophosphorylation and subsequent activation of the signal transduction pathways involved in regulating cellular proliferation, differentiation, and survival. Accordingly, this receptor carries out both redundant and restricted functions in the germline development of mammals and in the maintenance of various adult tissues. Correspondingly, the loss of EGFR regulation results in many human diseases, with the most notable cancer. This receptor is overexpressed and/or mutated in multiple epithelial-derived tumors, and associated with poor prognosis and survival in cancer patients. Here, we discuss in detail the role of EGFR in specific epithelial-derived cancer pathologies; these include lung cancer, colorectal cancer, and squamous cell carcinomas. The development of multiple anticancer agents against EGFR diminished the progression and metastasis of tumors. Some of the most versatile therapeutic anti-EGFR agents include the monoclonal antibodies (mAbs), demonstrating success in clinical settings when used in combination with cytotoxic treatments, such as chemotherapy and/or radiation. We thus discuss the development and application of two of the most notable therapeutic mAbs, cetuximab, and panitumumab, currently utilized in various EGFR-related epithelial cancers.

Kinase activity of ERBB3 contributes to intestinal organoids growth and intestinal tumorigenesis

As a member of the epidermal growth factor receptor (EGFR) family, ERBB3 plays an essential role in development and disease independent of inherently inactive kinase domain. Recently, ERBB3 has been found to bind to ATP and has catalytic activity in vitro. However, the biological function of ERBB3 kinase activity remains elusive in vivo. Here we have identified the physiological function of inactivated ERBB3 kinase activity by creating Erbb3‐K740M knockin mice in which ATP cannot bind to ERBB3. Unlike Erbb3 knockout mice, kinase‐inactive Erbb3^K740M homozygous mice were born in Mendelian ratios and showed normal development. After dextran sulfate sodium‐induced colitis, the kinase‐inactive Erbb3 mutant mice showed normal recovery. However, the outgrowth of ileal organoids by neuregulin‐1 treatment was more attenuated in Erbb3 mutant mice than in WT mice. Moreover, in combination with the Apc^Min mouse, the proportion of polyps less than 1 mm in diameter in mutant mice was higher than in control mice and an increase in the number of apoptotic cells was observed in polyps from mutant mice compared with polyps from control mice. Taken together, the ERBB3 kinase activity contributes to the outgrowth of ileal organoids and intestinal tumorigenesis, and the development of ERBB3 kinase inhibitors, including epidermal growth factor receptor family members, can be a potential way to target colorectal cancer.

Effect of KRAS mutational status on disease behavior and treatment outcome in patients with metastatic colorectal cancer: intratumor heterogeneity and mutational status

Background

Nowadays, the outcomes of metastatic colorectal cancer (mCRC) have considerably improved. Genetic studies evaluating KRAS mutational status are important in the personalized therapy era to understand disease heterogeneity, disease behaviors, and treatment outcomes.

Methods

This multicenter retrospective study evaluated 360 patients with mCRC treated at three oncology centers in Saudi Arabia and Egypt between February 2011 and December 2015. Patients were treated with bevacizumab and cetuximab according to guidelines. Therapy outcome, time to progression, and disease-associated death were assessed. KRAS mutational status was evaluated by testing exons 12 and 13.

Results

Approximately 220 (61.1%) cases were of wild-type KRAS, whereas KRAS mutation was noted in 38.9%. KRAS mutation was common in the descending colon, whereas a low incidence of the KRAS mutation was observed in the ascending colon (P<0.001). Among patients with KRAS mutation, 64.3% initially presented as emergency cases with obstruction/perforation (P=0.002), and 62.9% had hepatic or pulmonary metastasis. The progression-free survival (PFS) was 10.7 months. Cases without KRAS mutation showed a higher PFS than did those with KRAS mutation (mean PFS: 11.5 vs. 9.6 months, P=0.001). The overall survival was 23.2 months. The survival varied considerably according to KRAS type: patients without mutation survived for 25.0 months and those with mutation survived for 19.6 months (P<0.001). Disease-related death occurred in 132 (36.7%) cases, approximately 57.1% of them (80 cases) had KRAS mutations (P=0.001).

Conclusions

A major association between KRAS mutational status and both disease behavior and treatment outcomes was found in this study. Patients with KRAS mutation show advanced disease presentation, with lower PFS and overall survival.

Relationship between EGFR expression and subcellular localization with cancer development and clinical outcome

Epidermal growth factor receptor (EGFR) as a prevalent oncogene regulates proliferation, apoptosis and differentiation and thereby contributes to carcinogenesis. Even though, the documentation on its clinical relevance is surprisingly heterogeneous in the scientific literature. Here, we systematically investigated the correlation of mRNA to survival time and pathological parameters by analyzing 30 datasets in silico. Furthermore, the prognostic value of membrane-bound, cytoplasmic (mcEGFR) and nuclear expression (nEGFR) of EGFR was experimentally analyzed by immunohistochemical staining of 502 biopsies from 27 tumor types. We found that protein expression of EGFR showed better prognostic efficiency compared to mRNA, and that mcEGFR expression was positively correlated with nEGFR expression (p < 0.001). Unexpectedly, both mcEGFR and nEGFR expression were associated with low T stage (p < 0.001 and p = 0.004; respectively). Moreover, positive mcEGFR was significantly related to high differentiation (p = 0.027). No significant correlation was found with any other pathological parameters. Collectively, our results imply that the oncogenic function of EGFR may be more related to nascent stages of carcinogenesis than to advanced and progressive tumors, which may as well explain at least partially the occurrence of secondary resistance against EGFR-directed therapy.

Oncologic Outcomes in Metastatic Colorectal Cancer with Regorafenib with FOLFIRI as a Third- or Fourth-Line Setting

BACKGROUND

To evaluate the efficacy and toxicities of regorafenib plus irinotecan, dose-escalated on the basis of uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) genotyping, in previously heavily treated metastatic colorectal cancer (mCRC) and the prognostic values of EGFR expression, KRAS mutations, and tumor sidedness.

METHODS

Forty-one patients with mCRC with disease progression after treatment with fluoropyrimidines, oxaliplatin, irinotecan, anti-VEGF, and anti-EGFR MoAbs were subjected to UGT1A1 genotyping and received regorafenib combined with FOLFIRI with dose-escalated irinotecan.

RESULTS

The median follow-up period was 10.0 months (1.3-23.5 months). The overall disease control rate was 58.5%, whereas the median progression-free survival (PFS) and overall survival (OS) were 6.0 months and 12.0 months, respectively. KRAS mutations were significantly associated with positive EGFR expression (P = .026). KRAS mutations significantly correlated with a shorter OS than KRAS wild-type (6.0 vs. 14.4 months, P = .014) but had no significant association with PFS. Positive EGFR expression had an inverse correlation with PFS (2.5 vs. 14.0 months, P = .039) and OS (9.6 vs. 19.7 months, P = .044). Moreover, left-sided tumors associated with superior PFS (2.0 vs. 7.0 months, P < .0001) and OS (4.0 vs. 13.0 months, P < .0001), and tumor sidedness was an independent prognostic factor by the multivariate analysis.

CONCLUSION

Regorafenib and FOLFIRI concomitant therapy with dose-escalated irinotecan seemed to be potentially practicable with satisfactory oncological results. KRAS mutations and EGFR expression might be predictors of poor oncological outcomes; however, left-sided mCRCs would be more beneficial for concomitant regorafenib and FOLFIRI therapy.

Prognostic Value of NRAS Gene for Survival of Colorectal Cancer Patients: A Systematic Review and Meta-Analysis

Introduction: NRAS gene is associated with malignant proliferation and metastasis of colorectal cancer (CRC). But its prognostic value on CRC is still unknown. The objective of this study is to perform a meta-analysis to obtain its prognostic value on survival of CRC patients. Methods: The systematic review and meta-analysis was designed, undertaken and reported using items from the PRISMA statement. Relevant articles were identified through PubMed (containing Medline), Embase, Web of Science databases and Google scholar search engines from their inception up to October 3, 2016. The articles about NRAS on prognosis of CRC patients were enrolled. The association between NRAS and CRC survival time (including overall survival [OS], progression-free survival [PFS], and disease-free survival [DFS]) was evaluated using hazard ratio (HR) with its corresponding 95% confidence interval (CI). Results: A total of fifteen articles were included. High-expression of NRAS was significantly associated with poor OS (HR: 1.36, 95% CI: 1.15–1.61), and poor PFS (HR: 1.75, 95% CI: 1.04–2.94). The combined HR of NRAS on DFS was 0.87 (95% CI: 0.37–2.03). Subgroup analysis showed that NRAS was significantly associated with poor OS for patients from Western countries (HR: 1.38, 95% CI: 1.09–1.73), but not for those from Asian countries. Conclusions: This meta-analysis demonstrate that NRAS gene could predict the poor prognosis for the CRC patients. More large-sample cohort studies are needed to further confirm this conclusion.

Expression of epidermal growth factor receptor (EGFR) in colorectal cancer: An immunohistochemical study

BACKGROUND AND STUDY AIM

The epidermal growth factor receptor (EGFR) plays an important role in tumourigenesis and tumour progression of colorectal cancer (CRC) and leads to the activation of intracellular signaling pathways. The use of anti-EGFR-targeted therapy has increased for patients with metastatic CRC. Today, the clinical utility of immunohistochemistry has remained somewhat inconclusive. It is based on EGFR screening methods using paraffin-embedded tumour specimen to select patients eligible for treatment. There is still lack of agreement on reproducible scoring criteria for EGFR immunohistochemistry has in various clinical trials.

PATIENTS AND METHODS

We retrospectively reviewed 36 CRC patients who underwent surgeries during 2011 in Habib Thameur hospital in Tunis. We analyzed the immunohistochemical overexpression of EGFR using a score based on immunostaining intensity. In addition, we analyzed the correlation between this overexpression and patients' clinicopathologic parameters.

RESULTS

The positive expression rate of EGFR was 78% (28/36). Using the immunoreactivity score, 21 cases were considered low grade expression and 15 tumours were high grade. Immunohistochemical expression of EGFR showed a significant difference with tumour's location (p = 0.034) and vascular invasion (p = 0.03). This expression was not significantly associated with age, gender, tumour size, histological type, grade, TNM staging and perineural invasion.

CONCLUSIONS

EGFR expression by immunohistochemistry in CRC is variably correlated with clinicopathological parameters. Its assessment by this method has still not proved its predictive value.

Skin Disorders and Primary Tumor Location as Prognostic Factors in Patients with Metastatic Colorectal Cancer Treated with Cetuximab and Chemotherapy

Background:

Cetuximab-induced skin disorder is common in colorectal cancer (CRC), and is known to affect prolonged overall survival (OS). Patients with left-sided CRC survive longer than those with right-sided CRC, among those treated with combination cetuximab and chemotherapy. However, no study has evaluated patient prognosis in terms of OS and progression-free survival (PFS) in relation to both tumor location and skin disorder. This study aimed to determine the incidence of skin disorder according to tumor location and analyze the relationship of tumor location and skin disorder with OS.

Methods:

Patients with metastatic colorectal cancer (mCRC) treated with standard chemotherapy and cetuximab as first-line therapy were included. Differences in the incidence of skin disorders due to the location of the primary tumors were compared in the same patient. The OS and PFS in relation to the location of the primary tumors and presence or absence of skin disorder were also compared.

Results:

Total frequency of each skin disorder as rash acneiform, paronychia, and dry skin in patients with left- and right-sided mCRC was 70%, 70%, and 43% and 27%, 36%, and 27%, respectively. The median OS was 8.9 months for mCRC on the left-sided without skin disorder and 56.3 months for mCRC on the left-sided with skin disorder. In comparison, the median OS was 10.4 months for mCRC on the right-sided without skin disorder and 11.3 months for mCRC on the right-sided with skin disease (left-sided with skin disorder versus other three group; P<0.001).

Conclusions:

Primary tumor location and the presence of skin disorder are important factors in patients with mCRC who receive cetuximab. In particular, our results show the new fact that the left-sided and right-sided mCRC survival time were comparable if there is no skin disorder caused by cetuximab.

Engineered Charge Redistribution of Gp2 Proteins through Guided Diversity for Improved PET Imaging of Epidermal Growth Factor Receptor

The Gp2 domain is a protein scaffold for synthetic ligand engineering. However, the native protein function results in a heterogeneous distribution of charge on the conserved surface, which may hinder further development and utility. We aim to modulate charge, without diminishing function, which is challenging in small proteins where each mutation is a significant fraction of protein structure. We constructed rationally guided combinatorial libraries with charge-neutralizing or charge-flipping mutations and sorted them, via yeast display and flow cytometry, for stability and target binding. Deep sequencing of functional variants revealed effective mutations both in clone-dependent contexts and broadly across binders to epidermal growth factor receptor (EGFR), insulin receptor, and immunoglobulin G. Functional mutants averaged 4.3 charge neutralizing mutations per domain while maintaining net negative charge. We evolved an EGFR-targeted Gp2 mutant that reduced charge density by 33%, maintained net charge, and improved charge distribution homogeneity while elevating thermal stability ( Tm = 87 ± 1 °C), improving binding specificity, and maintaining affinity ( Kd = 8.8 ± 0.6 nM). This molecule was conjugated with 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid for 64Cu chelation and evaluated for physiological distribution in mice with xenografted A431 (EGFRhigh) and MDA-MB-435 (EGFRlow) tumors. Excised tissue gamma counting and positron emission tomography/computed tomography imaging revealed good EGFRhigh tumor signal (4.7 ± 0.5%ID/g) at 2 h post-injection and molecular specificity evidenced by low uptake in EGFRlow tumors (0.6 ± 0.1%ID/g, significantly lower than for non-charge-modified Gp2, p = 0.01). These results provide charge mutations for an improved Gp2 framework, validate an effective approach to charge engineering, and advance performance of physiological EGFR targeting for molecular imaging.

Selected proliferation markers correlated with dynamics of growth in colorectal cancer

For treatment of metastatic colorectal cancer, the dynamics of tumor growth is an important factor for treatment decision. However, it is difficult to evaluate the dynamics of tumor growth, especially those of synchronous metastatic diseases. This study aimed to find some indicators related to tumor proliferation to judge the dynamics of tumor progression. The pathological reports and clinical data of 1205 patients with metastatic colorectal cancer were retrospectively reviewed; 75 patients with known relapse time after radical resection were included, and the expression of proliferation-associated proteins was detected by immunohistochemistry. Relapse-free time (RFT) from radical resection to relapse was obtained to analyze the relationship with expression of these factors. Kaplan-Meier univariate analysis showed that the overexpression of cyclin D1 and epidermal growth factor receptor (EGFR) and late pathological stage after surgery indicated shorter RFT. Multivariate analysis showed that EGFR and the stage were independent predictors of RFT. Expression of EGFR and cyclin D1 and the pathological stage were included as combination risk factors for RFT analysis; more risk factors were correlated with shorter RFT. EGFR and cyclin D1 seemed to be indicators of the dynamics of tumor growth, and overexpression of those molecules may suggest rapid growth and poor prognosis.

Upregulation of c-mesenchymal epithelial transition expression and RAS mutations are associated with late lung metastasis and poor prognosis in colorectal carcinoma

The present study aimed to investigate whether c-mesenchymal epithelial transition factor (C-MET) overexpression combined with RAS (including KRAS, NRAS and HRAS) or BRAF mutations were associated with late distant metastases and the prognosis of patients with colorectal cancer (CRC). A total of 374 patients with stage III CRC were classified into 4 groups based on RAS/BRAF and C-MET status for comprehensive analysis. Mutations in RAS/BRAF were determined using Sanger sequencing and C-MET expression was examined using immunohistochemistry. The associations between RAS/BRAF mutations in combination with C-MET overexpression and clinicopathological variables including survival were evaluated. In addition, their predictive value for late distant metastases were statistically analyzed via logistic regression and receiver operating characteristic analysis. Among 374 patients, mutations in KRAS, NRAS, HRAS, BRAF and C-MET overexpression were observed in 43.9, 2.4, 0.3, 5.9 and 71.9% of cases, respectively. Considering RAS/BRAF mutations and C-MET overexpression, vascular invasion (P=0.001), high carcino-embryonic antigen level (P=0.031) and late distant metastases (P<0.001) were more likely to occur in patients of group 4. Furthermore, survival analyses revealed RAS/BRAF mutations may have a more powerful impact on survival than C-MET overexpression, although they were both predictive factors for adverse prognosis. Further logistic regression suggested that RAS/BRAF mutations and C-MET overexpression may predict late distant metastases. In conclusion, RAS/BRAF mutations and C-MET overexpression may serve as predictive indicators for metastatic behavior and poor prognosis of CRC.

RAS/BRAF Circulating Tumor DNA Mutations as a Predictor of Response to First-Line Chemotherapy in Metastatic Colorectal Cancer Patients

BACKGROUND

Since circulating tumor DNA (ctDNA) offers clear advantages as a minimally invasive method for tumor monitoring compared with tumor tissue, we aimed to evaluate genotyping ctDNA using a next-generation sequencing- (NGS-) based panel to identify the prognostic value of mutation status in metastatic colorectal cancer (mCRC) patients with primary tumor resected and with subsequent lines of treatment in this study.

METHODS

76 mCRC patients treated in Beijing Chao-Yang Hospital from 2011 to 2017 were enrolled. Genotyping of RAS/BRAF in tumor tissue and ctDNA was determined by ARMS PCR and with a 40-gene panel using NGS, respectively. Patient clinicopathologic features and RAS/BRAF gene mutation status were evaluated by survival analysis for disease-free survival (DFS) and progression-free survival (PFS).

RESULTS

Among 76 patients, KRAS distributions were not significantly correlated with any clinicopathologic features. The concordance between tumor tissue and ctDNA KRAS mutation was 81.25%. Mutations of RAS/BRAF had no significant impact on DFS after surgery (hazard ratio (HR), 1.205; 95% CI, 0.618 to 2.349; P = 0.5837) but prognosticated poorer PFS in subsequent first-line therapy (HR, 3.351; 95% CI, 1.172 to 9.576; P = 0.024).

CONCLUSION

ctDNA was comparable with tumor tissue for mutation detection. RAS/BRAF mutations detected in ctDNA predict a worse PFS in mCRC patients with first-line chemotherapy. Our results provide support for the prognostic value of RAS/BRAF ctDNA mutation detection in mCRC patients.

EGFR expression in patients with stage III colorectal cancer after adjuvant chemotherapy and on cancer cell function

The epidermal growth factor receptor (EGFR)/RAS/RAF/MEK/MAPK pathway plays a crucial role in the carcinogenesis, invasion and metastasis of colorectal cancer (CRC). However, its role in the prognosis and prediction of relapse in patients with stage III CRC after adjuvant chemotherapy remains controversial. In the present study, the clinicopathological features of 173 patients with stage III CRC who underwent radical resection and adjuvant chemotherapy with the fluoropyrimidine/folinic acid, and oxaliplatin (FOLFOX) regimen, and their prognostic values of EGFR expression were retrospectively analyzed. By conducting an in vitro CRC cell line study through the knockdown of EGFR expression, we analyzed cell proliferation, colony formation and migration. Positive EGFR expression and an abnormal postoperative serum carcinoembryonic antigen (CEA) level were found to be significant independent negative predictive factors for postoperative relapse. Furthermore, positive EGFR expression was a significant independent negative prognostic factor for disease-free survival (DFS) and overall survival (OS). Additionally, an in vitro cell line study showed that the knockdown of EGFR expression significantly reduced CRC cell proliferation, colony formation and migration. The results of in vitro and in vivo experiments demonstrated that EGFR expression had a prognostic value for OS and DFS, as well as predictive roles for postoperative relapse, in patients with stage III CRC. By analyzing both EGFR expression and the postoperative CEA, the patients with stage III CRC who were at a high risk of postoperative relapse, or mortality following adjuvant chemotherapy could be identified. In short, CRC cells with EGFR expression would exhibit a highly malignant behavior.

Association between clinicopathological features and survival in patients with primary and paired metastatic colorectal cancer and KRAS mutation

The KRAS gene mutation is involved in several types of tumors. However, the potential role of the KRAS mutation in human primary and paired metastatic colorectal cancer (CRC) among different nationalities is poorly understood. In the present study, we assessed the relationship between KRAS mutation status and overall survival (OS) and disease-free survival (DFS) in 230 patients with primary and paired metastatic CRC. The KRAS mutation rate in primary CRC tissue was 43.0% (99/230), which was higher than in paired metastatic CRC, which was 31.9% (23/72; P<0.001). Clinicopathologically, the KRAS gene mutation rate was higher in tumors that had infiltrated more deeply (T3, T4) and in lymph node (LN) metastases (N1/N2) (P=0.029 and P=0.010, respectively). The KRAS gene status did not differ between the Han and Uyghur nationalities in both primary and metastatic CRC. In 72 paired cases, the KRAS mutation rate in primary CRC was significantly higher than in metastatic CRC (P<0.001) and in metastatic CRC that had infiltrated more deeply (T3, T4) (P=0.034). In the metastatic cases, the KRAS gene mutation rate was higher in patients aged over 65 years (P=0.035). Specifically, KRAS mutation was correlated with a poorer OS and DFS (P=0.004 and P=0.029, respectively). In our study, 35 patients with wild-type KRAS who received cetuximab targeted therapy had a better DFS than patients with mutant KRAS (P=0.029). The results of the current study demonstrate that the KRAS status is significantly associated with infiltrating LN metastases and the TNM stage in primary CRC. In addition, the results show that the KRAS mutation is significantly more common in primary tumors than in paired metastatic CRC, and the KRAS mutation is correlated with a shorter OS and DFS, as patients with wild-type KRAS who received cetuximab experienced a longer DFS.

High expression of PFTK1 in cancer cells predicts poor prognosis in colorectal cancer

The serine/threonine-protein kinase PFTAIRE 1 (PFTK1) is a member of the cyclin‑dependent kinase family that is highly expressed in several malignant tumors, including hepatocellular carcinoma, esophageal, breast and gastric cancers, and glioma. It contributes to tumor progression and influences tumor prognosis. However, the expression and clinicopathological significance of PFTK1 in human colorectal cancer (CRC) remain to be elucidated. The present study aimed to examine the expression of PFTK1 and to evaluate the clinical significance of its expression in human CRC. Reverse transcription‑quantitative polymerase chain reaction was performed on 10 fresh CRC and 10 surrounding normal tissue samples to detect and compare the expression of PFTK1 mRNA in CRC and normal colorectal tissues. Immunohistochemistry was performed on 179 CRC tissue specimens and 47 control samples of normal colorectal lesions to characterize the expression of PFTK1 protein. Kaplan‑Meier overall survival (OS) rate and Cox regression analyses were performed to evaluate the prognosis of patients with CRC. The expression of PFTK1 mRNA in CRC tissues (1.433±0.168) was significantly higher compared with normal tissues (0.853±0.107; t=1.97 ('t' was the value obtained from quantification of the mRNA data, following a paired t‑test), P=0.008). High PFTK1 expression in cancerous cells was detected in 92 of the CRC specimens (51.40%), and high levels of PFTK1 were associated with tumor node metastasis (TNM) stage (P=0.042), tumor classification (P=0.022) and preoperative carcinoembryonic antigen (CEA) level (P<0.001). Kaplan‑Meier OS rate and Cox regression analysis revealed that high PFTK1 expression level (hazard ratio (HR)=1.999; P=0.019) was an independent prognostic factor of CRC patients. The degree of differentiation (HR, 0.368, P=0.003), TNM classification (HR, 2.118, P=0.001) and preoperative CEA level (HR, 2.302, P=0.003) were also predictors of the prognosis of patients with CRC. The present study suggested that PFTK1 may be a potential anticancer target and prognostic marker in patients with CRC.

Overexpression of MutL homolog 1 and MutS homolog 2 proteins have reversed prognostic implications for stage I-II colon cancer patients

BACKGROUND

The outcome of colon cancer patients without lymph node metastasis is heterogeneous. Searching for new prognostic markers is warranted.

METHODS

One hundred twenty stage I-II colon cancer patients who received complete surgical excision during 1995-2004 were selected for this biomarker study. Immunohistochemical method was used to assess p53, epidermal growth factor receptor, MLH1, and MSH2 status. KRAS mutation was examined by direct sequencing.

RESULTS

Thirty three patients (27.5%) developed metachronous metastasis during follow up. By multivariate analysis, only female gender (p = 0.03), high serum carcinoembryonic antigen (CEA) level (≧5 ng/ml) (p = 0.04), and MLH1 overexpression (p = 0.003) were associated with the metastasis group. The 5-year-survival rate were also significantly lower for female gender (71.7% versus 88.9%, p = 0.025), high CEA level (64.9% versus 92.4%, p < 0.001), and MLH1 overexpression (77.5% versus 94.4%, p = 0.039). In contrast, MSH2 overexpression was associated with better survival, 95.1% versus 75.5% (p = 0.024).

CONCLUSIONS

The reversed prognostic implications in the overexpression of MLH1 and MSH2 for stage I-II colon cancer patients is a novel finding and worthy of further confirmation.

Coexistence of MSI with KRAS mutation is associated with worse prognosis in colorectal cancer

Kristen rat sarcoma viral oncogene homolog (KRAS) and microsatellite instability (MSI) are prognostic markers of colorectal cancer (CRC). However, the clinical value is still not fully understood, when giving the consideration to both the molecular makers. Five hundred fifty-one patients with CRC were retrospectively assessed by determining their clinicopathological features. KRAS mutations were detected by polymerase chain reaction. MSI, a defect in the mismatch repair (MMR) system, was detected by immunohistochemistry. The prognostic value of KRAS in combination with MSI was studied. Among 551 CRC patients, mutations in KRAS codon 12 and KRAS codon 13 were detected in 34.5% and 10.5% of patients, respectively. Four hundred one tumors were randomly selected to detect for MMR proteins expression. In this analysis, 30 (7.5%) tumors that had at least 1 MMR protein loss were defined as MMR protein-deficient (MMR-D), and the remaining tumors were classed as MMR protein-intact (MMR-I). According to KRAS mutation and MSI status, CRC was classified into 4 groups: Group 1, KRAS-mutated and MMR-I; Group 2, KRAS-mutated and MMR-D; Group 3, KRAS wild and MMR-I; and Group 4, KRAS wild and MMR-D. We found that patients in Group4 had the best prognosis. In conclusion, combination status of KRAS and MSI status may be used as a prognostic biomarker for CRC patient, if validated by larger studies.

64Cu-Labeled Gp2 Domain for PET Imaging of Epidermal Growth Factor Receptor

This purpose of this study is to determine the efficacy of a 45-amino acid Gp2 domain, engineered to bind to epidermal growth factor receptor (EGFR), as a positron emission tomography (PET) probe of EGFR in a xenograft mouse model. The EGFR-targeted Gp2 (Gp2-EGFR) and a nonbinding control were site-specifically labeled with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator. Binding affinity was tested toward human EGFR and mouse EGFR. Biological activity on downstream EGFR signaling was examined in cell culture. DOTA-Gp2 molecules were labeled with ⁶⁴Cu and intravenously injected (0.6-2.3 MBq) into mice bearing EGFR^high (n = 7) and EGFR^low (n = 4) xenografted tumors. PET/computed tomography (CT) images were acquired at 45 min, 2 h, and 24 h. Dynamic PET (25 min) was also acquired. Tomography results were verified with gamma counting of resected tissues. Two-tailed t tests with unequal variances provided statistical comparison. DOTA-Gp2-EGFR bound strongly to human (K_D = 7 ± 5 nM) and murine (K_D = 29 ± 6 nM) EGFR, and nontargeted Gp2 had no detectable binding. Gp2-EGFR did not agonize EGFR nor antagonize EGF-EGFR. ⁶⁴Cu-Gp2-EGFR tracer effectively localized to EGFR^high tumors at 45 min (3.2 ± 0.5%ID/g). High specificity was observed with significantly lower uptake in EGFR^low tumors (0.9 ± 0.3%ID/g, p < 0.001), high tumor-to-background ratios (11 ± 6 tumor/muscle, p < 0.001). Nontargeted Gp2 tracer had low uptake in EGFR^high tumors (0.5 ± 0.3%ID/g, p < 0.001). Similar data was observed at 2 h, and tumor signal was retained at 24 h (2.9 ± 0.3%ID/g). An engineered Gp2 PET imaging probe exhibited low background and target-specific EGFR^high tumor uptake at 45 min, with tumor signal retained at 24 h postinjection, and compared favorably with published EGFR PET probes for alternative protein scaffolds. These beneficial in vivo characteristics, combined with thermal stability, efficient evolution, and small size of the Gp2 domain validate its use as a future class of molecular imaging agents.

Clinical Implications and Future Perspectives of Circulating Tumor Cells and Biomarkers in Clinical Outcomes of Colorectal Cancer

Colorectal cancer (CRC) is a major public health problem. Early CRC detection, pretherapeutic responsiveness prediction, and postoperative micrometastasis monitoring are the hallmarks for successful CRC treatment. Here, the methodologies used for detecting circulating tumor cells (CTCs) from CRC are reviewed. In addition to the traditional CRC biomarkers, the persistent presence of posttherapeutic CTCs indicates resistance to adjuvant chemotherapy and/or radiotherapy; hence, CTCs also play a decisive role in the subsequent relapse of CRC. Moreover, the genetic and phenotypic profiling of CTCs often differs from that of the primary tumor; this difference can be used to select the most effective targeted therapy. Consequently, studying CTCs can potentially individualize treatment strategies for patients with CRC. Therefore, CTC detection and characterization may be valuable tools for refining prognosis, and CTCs can be used in a real-time tumor biopsy for designing individually tailored therapy against CRC.

Blood-based markers of efficacy and resistance to cetuximab treatment in metastatic colorectal cancer: results from CALGB 80203 (Alliance)

Circulating protein markers were assessed in patients with colorectal cancer (CRC) treated with cetuximab in CALGB 80203 to identify prognostic and predictive biomarkers. Patients with locally advanced or metastatic CRC received FOLFOX or FOLFIRI chemotherapy (chemo) or chemo in combination with cetuximab. Baseline plasma samples from 152 patients were analyzed for six candidate markers [epidermal growth factor (EGF), heparin‐binding EGF (HBEGF), epidermal growth factor receptor (EGFR), HER2, HER3, and CD73]. Analyte levels were associated with survival endpoints using univariate Cox proportional hazards models. Predictive markers were identified using a treatment‐by‐marker interaction term in the Cox model. Plasma levels of EGF, HBEGF, HER3, and CD73 were prognostic for overall survival (OS) across all patients (KRAS mutant and wild‐type). High levels of EGF predicted for lack of OS benefit from cetuximab in KRAS wild‐type (WT) patients (chemo HR = 0.98, 95% CI = 0.74–1.29; chemo+cetuximab HR = 1.54, 95% CI = 1.05–2.25; interaction P = 0.045) and benefit from cetuximab in KRAS mutant patients (chemo HR = 1.72, 95% CI = 1.02–2.92; chemo+cetuximab HR = 0.90, 95% CI = 0.67–1.21; interaction P = 0.026). Across all patients, higher HER3 levels were associated with significant OS benefit from cetuximab treatment (chemo HR = 4.82, 95% CI = 1.68–13.84; chemo+cetuximab HR = 0.95, 95% CI = 0.31–2.95; interaction P = 0.046). CD73 was also identified as predictive of OS benefit in KRASWT patients (chemo HR = 1.28, 95% CI = 0.88–1.84; chemo+cetuximab HR = 0.60, 95% CI = 0.32–1.13; interaction P = 0.049). Although these results are preliminary, and confirmatory studies are necessary before clinical application, the data suggest that HER3 and CD73 may play important roles in the biological response to cetuximab.

Preclinical and clinical studies on afatinib in monotherapy and in combination regimens: Potential impact in colorectal cancer

Targeting the epidermal growth factor receptor (EGFR) with monoclonal antibodies (mAbs) or tyrosine kinase inhibitors (TKI) has been an interesting therapeutic strategy because aberrant activation of this receptor plays an important role in the tumorgenesis of many cancer types, including colorectal cancer (CRC). After the initial promising results of EGFR-targeted therapies, therapeutic resistance is a major clinical problem. In order to overcome resistance to these EGFR-targeted therapies, new treatment options are necessary. In contrast to first generation EGFR inhibitors, afatinib (BIBW2992) is a second-generation irreversible ErbB family blocker that inhibits EGFR as well as HER2 and HER4. Consequently, treatment with afatinib may result in a distinct and more pronounced therapeutic benefit. Preclinical studies have reported promising results for afatinib in monotherapy as well as in combination with other drugs in CRC model systems. Furthermore, clinical studies examining afatinib as single agent and in combination therapy demonstrated manageable safety profile. Nevertheless, only limited antitumor activity has been observed in CRC patients. Although several combination treatments with afatinib have already been investigated, no optimal combination has been identified for CRC patients yet. As molecular tumor characteristics have gained increased importance in the choice of treatment, additional studies with biomarker-driven patient recruitment are required to further explore afatinib efficacy in CRC.

Mutation spectra of RAS gene family in colorectal cancer

BACKGROUND

The clinicopathologic features and frequency of KRAS mutations in colorectal cancer (CRC) patients have been reported; however, the characteristics and impact of NRAS and HRAS mutations on the survival of CRC patients have seldom been addressed.

METHODS

Under institutional review board approval, 1,519 CRC patients who underwent surgery were enrolled. Mutation status of RAS was determined by polymerase chain reaction and mass spectrophotometry.

RESULTS

The frequency of KRAS, NRAS, and HRAS mutations was 39.6%, 4.3%, and 1.7%, respectively. The KRAS mutation was associated with fewer left-sided tumors, fewer poor differentiated tumors, more mucin component, and less lymphovascular invasion. The NRAS or HRAS mutations were not associated with any of the clinicopathologic features examined. After univariate analysis, only NRAS mutation was associated with patients' overall and disease-free survival. However, the association of NRAS with patients' overall and disease-free survival disappeared after stepwise elimination.

CONCLUSIONS

This study demonstrates the clinicopathologic characteristics of CRC patients with RAS mutations. Patients with NRAS mutation tended to have worse outcomes.

Dual targeting of HER3 and EGFR in colorectal tumors might overcome anti-EGFR resistance

Multiple genetic alterations have been associated with resistance to anti-EGFR therapy in metastatic colorectal cancer (CRC) patients. Research has been mainly focused on driver mutations in KRAS, NRAS, BRAF and PI3K. However, recent evidence suggests a crucial role for non-genetic mechanisms in conferring resistance to anti-EGFR therapy. Specifically, the HER3 receptor is capable of heterodimerizing with multiple EGFR family members resulting in downstream activation of the PI3K and MAPK pathways. Monoclonal antibodies targeted against the HER3 receptor are being investigated in clinical trials; however, preliminary data has shown limited clinical activity. Thus, given the relevance of the HER3 receptor in activating downstream effector pathways and in conferring resistance to anti-EGFR therapy, the therapeutic targeting of HER3 in combination with primary drivers of the tumor is also being investigated. Here, we review the role of HER3 as a promoter of clinical resistance to EGFR therapy and discuss therapeutic approaches that could potentially overcome this resistance.

LINC01225 promotes occurrence and metastasis of hepatocellular carcinoma in an epidermal growth factor receptor-dependent pathway

The long noncoding RNAs (lncRNAs) have long been clarified to participate in hepatocellular carcinoma (HCC) as a biomarker. We carried out the present study in order to identify HCC-related lncRNAs and elucidate the functional roles in the development and progression of HCC. Our previous study has provided that LINC01225 may be an HCC-related gene. Here, we verified that LINC01225 was upregulated in HCC. Knockdown of LINC01225 resulted in inhibited cell proliferation and invasion with activated apoptosis and cell cycle arrest in vitro. Overexpression of LINC01225 in LINC01225 knockdown cells presented that attenuated cell proliferation and invasion were restored and enhanced. Subcutaneous and tail vein/intraperitoneal injection xenotransplantation model in vivo validated reduced tumor progression and metastasis. Investigation of mechanism found that LINC01225 could bind to epidermal growth factor receptor (EGFR) and increase the protein level of EGFR, and subsequently fine tune the EGFR/Ras/Raf-1/MEK/MAPK signaling pathway. Analysis with clinicopathological information suggested a high expression of LINC01225 is positively associated with poor prognosis. We also proved that LINC01225 was stably expressed in serum and can act as a novel biomarker in predicting the diagnosis of HCC. As a conclusion, LINC01225 plays a crucial role in HCC and can act as a biomarker for the diagnosis and prognosis of HCC.

Influence of mRNA expression of epiregulin and amphiregulin on outcome of patients with metastatic colorectal cancer treated with 5-FU/LV plus irinotecan or irinotecan plus oxaliplatin as first-line treatment (FIRE 1-trial)

Our aim was to investigate the impact of EREG and AREG mRNA expression (by RT-qPCR) in patients with metastatic colorectal cancer (mCRC). In addition, epidermal growth factor receptor (EGFR) expression (by immunohistochemistry) as well as RAS-and PIK3CA-mutations (by pyrosequencing) were assessed. Tumors of 208 mCRC patients receiving 5-fluorouracil/leucovorin plus irinotecan (FUFIRI) or irinotecan plus oxaliplatin (mIROX) within the FIRE-1 trial were analyzed for mutations. Molecular characteristics were correlated with response, progression-free survival (PFS), overall survival (OS). mRNA expression was evaluated using ROC-analysis in 192 tumors (AREG high n = 31 vs. low n = 161; EREG high n = 89 vs. low n = 103). High versus low AREG expression was associated with PFS of 10.0 versus 8.0 months (HR = 0.62, 95% CI: 0.402-0.940, p = 0.03) and OS of 24.6 versus 18.7 months (HR = 0.72, 95% CI: 0.476-1.078, p = 0.11). High versus low EREG expression correlated with prolonged PFS (9.4 vs. 6.8 months, HR = 0.62, 95% CI: 0.460-0.846, p = 0.002) and OS (25.8 vs. 15.5 months, HR = 0.48, 95% CI: 0.351-0.657, p < 0.001). The positive prognostic effect of high EREG expression was confirmed in a multivariate analysis and was neither affected by EGFR expression nor by mutations of RAS- and PIK3CA-genes. EREG expression appears as an independent prognostic marker in patients with mCRC receiving first-line irinotecan-based chemotherapy.

Expression of Vascular Endothelial Growth Factor (VEGF) and Epidermal Growth Factor Receptor (EGFR) in Patients With Serous Ovarian Carcinoma and Their Clinical Significance

Background:

Vascular endothelial growth factor (VEGF) has an essential role in tumor metastasis by inducing the construction of abnormal blood vessels. Epidermal growth factor receptor (EGFR) is involved in different parts of cancer growth such as tumor initiation, angiogenesis and metastasis.

Objectives:

The aim of this study was to evaluate the expression of VEGF and EGFR in ovarian cancer in southern Iran and to assess the correlation between expression of these two markers and patients’ age, tumor stage, and grade.

Patients and Methods:

In this cross-sectional study, 50 paraffin blocks of serous ovarian adenocarcinomas and 50 paraffin-embedded specimens from control individuals operated for reasons other than malignancy were immunohistochemically stained using anti-human VEGF and EGFR antibodies.

Results:

A significant difference in the frequency of positive expression of VEGF was observed in ovarian cancer patients (25.0%) compared with the control group (8.0%) (P = 0.023). A significant difference between EGFR expression in patients (56.8%) and controls (24.0%) was also obtained (P = 0.001). No significant correlation between VEGF and EGFR expression and patients’ age, tumor grade and stage were detected (P > 0.05).

Conclusions:

The significant increase in both VEGF and EGFR in the patients with ovarian cancer compared to healthy individuals could have prognostic value. Identifying these markers may be useful for chemopreventive and chemotherapeutic strategies for patients with serous ovarian cancer.

Translational progress on tumor biomarkers

There is an urgent need to apply basic research achievements to the clinic. In particular, mechanistic studies should be developed by bench researchers, depending upon clinical demands, in order to improve the survival and quality of life of cancer patients. To date, translational medicine has been addressed in cancer biology, particularly in the identification and characterization of novel tumor biomarkers. This review focuses on the recent achievements and clinical application prospects in tumor biomarkers based on translational medicine.

High Rab27A expression indicates favorable prognosis in CRC

Background

Rab27A is a peculiar member in Rab family and has been suggested to play essential roles in the development of human cancers. However, the association between Rab27A expression and clinicopathological characteristics of colorectal cancer (CRC) has not been elucidated yet.

Methods

One-step quantitative real-time polymerase chain reaction (qPCR) test with 18 fresh-frozen CRC samples and immunohistochemistry (IHC) analysis in 112 CRC cases were executed to evaluate the relationship between Rab27A expression and the clinicopathological features of CRC. Cox regression and Kaplan-Meier survival analyses were performed to identify the prognostic factors for 112 CRC patients.

Results

The results specified that the expression levels of Rab27A mRNA and protein were significantly higher in CRC tissues than that in matched non-cancerous tissues, in both qPCR test (p = 0.029) and IHC analysis (p = 0.020). The IHC data indicated that the Rab27A protein expression in CRC was statistically correlated with lymph node metastasis (p = 0.022) and TNM stage (p = 0.026). Cox multi-factor analysis and Kaplan-Meier method suggested Rab27A protein expression (p = 0.012) and tumor differentiation (p = 0.004) were significantly associated with the overall survival of CRC patients.

Conclusion

The data indicated the differentiate expression of Rab27A in CRC tissues and matched non-cancerous tissues. Rab27A may be used as a valuable prognostic biomarker for CRC patients.

Up-front systemic chemotherapy is a feasible option compared to primary tumor resection followed by chemotherapy for colorectal cancer with unresectable synchronous metastases

Background

In stage IV colorectal cancer (CRC) with unresectable metastases, whether or not resection of the primary tumor should be indicated remains controversial. We aim to determine the impact of primary tumor resection on the survival of stage IV CRC patients with unresectable metastases.

Methods

We retrospectively investigated 103 CRC patients with stage IV colorectal cancer with metastases, treated at Hiroshima University Hospital between 2007 and 2013. Of these, those who had resectable primary tumor but unresectable metastases and received any chemotherapy were included in the study. We analyzed the overall survival (OS) and short-term outcomes between the patients who received up-front systemic chemotherapy (USC group) and those who received primary tumor resection followed by chemotherapy (PTR group).

Results

Of the 57 included patients, 15 underwent USC and 42 PTR. The median survival times were 13.4 and 23.9 months in the USC and PTR groups, respectively (P = 0.093), but multivariate analysis for the overall survival showed no significant difference between the two groups (hazard ratio, 1.30; 95% confidence interval (CI), 0.60 to 2.73, P = 0.495). In the USC group, the disease control rate of primary tumor was observed in 12 patients (80.0%), but emergency laparotomy was required for 1 patient. Morbidity in the PTR group was observed in 18 cases (42.9%).

Conclusions

The overall survival did not differ significantly between the USC and PTR groups. USC may help avoid unnecessary resection and consequently the high morbidity rate associated with primary tumor resection for stage IV CRC with unresectable metastases.

High SHIP2 expression indicates poor survival in colorectal cancer

SH2-containing inositol 5′-phosphatase 2 (SHIP2), which generally regulates insulin signaling, cytoskeleton remodeling, and receptor endocytosis, has been suggested to play a significant role in tumor development and progression. However, the associations between SHIP2 expression and the clinical features to evaluate its clinicopathologic significance in colorectal cancer (CRC) have not been determined yet. In the present study, one-step quantitative real-time polymerase chain reaction (qPCR) test and immunohistochemistry (IHC) analysis with CRC tissue microarrays (TMA) were employed to evaluate the mRNA and protein expression of SHIP2 in CRC. The results showed that SHIP2 expression in the mRNA and protein levels was significantly higher in CRC tissues than that in corresponding noncancerous tissues (both P < 0.05). The expression of SHIP2 protein in CRC was related to lymph node metastasis (P = 0.036), distant metastasis (P = 0.001), and overall survival (P = 0.009). Kaplan-Meier method and Cox multifactor analysis suggested that high SHIP2 protein level (P = 0.040) and positive distant metastasis (P = 0.048) were critically associated with the unfavorable survival of CRC patients. The findings suggested that SHIP2 may be identified as a useful prognostic marker in CRC and targeting CRC may provide novel strategy for CRC treatment.

Localization of phosphorylated ErbB1-4 and heregulin in colorectal cancer

Background

The ErbB family consists of four proteins including (EGFR)/ErbB1, ErbB2, ErbB3, and ErbB4, and plays a crucial role in the promotion of multiple tumorigenic processes. In addition to the traditional pathways of EGFR signaling, EGFR translocates to the nucleus and acts as a transcription factor in the proliferation of cancer cells. Heregulin is known as both an ErbB3 and an ErbB4 ligand. This study aimed to investigate the expression of heregulin and its relevant EGFR family members as well as their phosphorylated forms in human colorectal cancer (CRC) tissues and to determine the relationship between their expression and clinicopathological factors including patient prognosis.

Methods

We analyzed the effects of exogenous heregulin on ErbB2, ErbB3 and ErbB4 phosphorylation in Caco-2, DLD-1, and HCT 116 colon cancer cell lines by western blot analysis. We examined 155 surgical resections from colorectomy patients. Cellular localization of ErbB1-4, their phosphorylated forms and heregulin protein was analyzed in CRC surgical resections by immunohistochemical analysis. Immunohistochemical results were compared with clinicopathological factors and patient prognosis.

Results

Phosphorylated ErbB2 (pErbB2) and phosphorylated ErbB3 (pErbB3) were detected in both nuclear and cytosolic fractions of Caco-2 and DLD-1 cells stimulated by exogenous heregulin. Whereas, phosphorylated ErbB4 (pErbB4) was detected only in cytosolic fractions of HCT 116 cells stimulated by exogenous heregulin. Phosphorylated EGFR (pEGFR) immunoreactivity was observed in the cytoplasm and nuclei of cancer cells, whereas the pattern of EGFR staining was membranous and cytoplasmic. Subcellular localization of pErbB2, cytoplasmic, membranous, or nuclear, varied among cases. pErbB3 immunoreactivity was exclusively observed in the nuclei of cancer cells. pErbB4 immunoreactivity was observed in the cell membrane of cancer cells. Statistically, heregulin immunoreactivity correlated with pErbB2 and pErbB4 expression. In multivariate analysis for disease free survival, lymph node status, pErbB3 and pErbB4 expression retained independent prognostic significance. In multivariate analysis for overall survival, lymph node status, pEGFR and pErbB4 retained independent prognostic significance.

Conclusions

ErbB2 and ErbB3 phosphorylated by heregulin localized in the nucleus of CRC cells. Phosphorylated ErbB1-4 and heregulin contribute to poorer patient prognosis in CRC. This heregulin-ErbB family member autocrine loop may be a candidate for targeted treatment of CRC.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-863) contains supplementary material, which is available to authorized users.

KRAS mutation in adenocarcinoma of the gastrointestinal type arising from a mature cystic teratoma of the ovary

Mature cystic teratomas (MCT) in the ovary rarely undergo malignant transformation. Moreover, adenocarcinoma of the gastrointestinal type is much rarer. We present two cases of perimenopausal female pateints with mature cystic teratoma of single ovary, while local adenocarcinoma arising in the MCT. The malignancies showed immunohistochemical features of intestinal differentiation, such as strong positivity for CDX-2, villin and CK-20, and negativity for CK-7. Furthermore, the mutation analysis of molecular alteration revealed a KRAS gene mutation in the intestinal adenocarcinoma part, extending into benign intestinal-type epithelium linings. Yet the mutation was not present in the epidermal component of the teratoma. We present these as two unique cases of mucinous adenocarcinoma of the intestinal type arising from mature cystic teratoma. Moreover, we also submit that this KRAS mutation might contribute to identify malignant transformation of a MCT and suggest possible effect on targeted treatment decisions for anti-epidermal growth factor receptor (EGFR) therapy in metastasized patients.