HER2 diagnostics in gastric cancer-guideline validation and development of standardized immunohistochemical testing

Diagnostic Mutation Profiling and Validation of Non-Small-Cell Lung Cancer Small Biopsy Samples using a High Throughput Platform

BACKGROUND

A single platform designed for the synchronous screening of multiple mutations can potentially enable molecular profiling in samples of limited tumor tissue. This approach is ideal for the assessment of advanced non-small-cell lung cancer (NSCLC) diagnostic specimens, which often comprise small biopsies. Therefore, we aimed in this study to validate the mass spectrometry-based Sequenom LungCarta panel and MassARRAY platform using DNA extracted from a single 5 μM formalin-fixed paraffin-embedded tissue section.

METHODS

Mutations, including those with an equivocal spectrum, detected in 90 cases of NSCLC (72 lung biopsies, 13 metastatic tissue biopsies, three resections, and two cytology samples) were validated by a combination of standard sequencing techniques, immunohistochemical staining for p53 protein, and next-generation sequencing with the TruSight Tumor panel.

RESULTS

Fifty-five mutations were diagnosed in 47 cases (52%) in the following genes: TP53 (22), KRAS (15), EGFR (5), MET (3), PIK3CA (3), STK11 (2), NRF-2 (2), EPHA5 (1), EPHA3 (1), and MAP2K1 (1). Of the 90 samples, one failed testing due to poor quality DNA. An additional 7 TP53 mutations were detected by next-generation sequencing, which facilitated the interpretation of p53 immunohistochemistry but required 5 × 10 μM tumor sections per sample tested.

CONCLUSIONS

The LungCarta panel is a sensitive method of screening for multiple alterations (214 mutations across 26 genes) and which optimizes the use of limited amounts of tumor DNA isolated from small specimens.

HER2 testing in gastric and gastroesophageal adenocarcinomas

The human epidermal growth factor receptor 2 (HER2) is overexpressed in 10% to 35% of gastric and gastroesophageal junction (GEJ) adenocarcinomas. In 2010, the phase III Trastuzumab for Gastric Cancer (ToGA) trial showed that addition of the anti-HER2 monoclonal antibody trastuzumab to chemotherapy significantly improved survival of patients with advanced or metastatic tumors that were positive for HER2 overexpression. As a result, HER2 testing is now recommended for all patients with advanced or metastatic disease, although there is still some debate as to the optimal methods of assessment. HER2 expression in gastric and GEJ tumors shows several differences compared with breast tumors and, for this reason, the proposed criteria for scoring HER2 expression in biopsies and resections of gastric and GEJ carcinomas differ from those used in breast carcinomas. This review discusses what is currently known about the patterns of HER2 expression in gastric and GEJ adenocarcinomas, summarizes the findings of the ToGA trial and its clinical implications, and provides an overview of the recommended guidelines for the most accurate evaluation of HER2 status in gastric and GEJ cancer.

Update on metastatic gastric and esophageal cancers

Cancers of the stomach and esophagus are among the most challenging cancers of the GI tract to treat, associated with poor median survivals for metastatic disease and significant, sometimes prolonged, deteriorations in patient performance status as the diseases progress. However, in the past decade, we have begun to better understand disease biology and carcinogenesis, leading to the identification of subtypes of these diseases. There is also an increasing awareness of the global heterogeneity of disease and its impact on drug development. Our improved understanding of the molecular underpinnings of gastric and esophageal cancers has been accompanied with the development of novel therapeutic strategies. Recent actively investigated targets in this disease include human epidermal growth factor receptor 2, angiogenesis, MET, and immune checkpoint inhibition, with approvals of two new targeted agents, trastuzumab and ramucirumab. Improvements in our ability to deliver cytotoxic therapy, which is better tolerated and allows patients an opportunity to benefit from second- and more advanced lines of therapy, have also been observed. In this review, the current state-of-the-art management of advanced and metastatic gastric and esophageal adenocarcinomas, specifically highlighting the development of targeted therapies in these diseases, is described.

Is the current diagnostic algorithm reliable for selecting cases for EGFR- and KRAS-mutation analysis in lung cancer?

OBJECTIVES

Adenocarcinoma (ADC) of the lung may harbor EGFR- or KRAS-mutations, which are relevant for treatment decisions. There is no consensus on the percentages of EGFR- and KRAS-mutations that are allowed to be missed by a diagnostic algorithm, although a percentage of less than 1% for EGFR-mutations has been suggested. The current guidelines do not advise to perform EGFR-mutation analysis in unequivocal squamous cell carcinoma (SqCC). For KRAS-mutations no threshold for missing cases is suggested yet. To improve segregation between ADC and SqCC in small samples, the classification of lung cancer was updated in 2011, adding immunohistochemistry (IHC) for p63 and TTF-1 to the diagnostic algorithm. In this study we examined how many cases with an EGFR- or KRAS-mutation in our database would have been missed, if the current guideline for selecting cases for mutation analysis would have been applied.

MATERIALS AND METHODS

From an institutional lung cancer database of specimens analyzed for EGFR- and KRAS-mutations (n=816), cases harboring a mutation without being treated prior with an EGFR-TKI were selected (n=336). Corresponding original histological diagnoses and IHC for TTF-1, p63 and PAS-D were collected. Cases with SqCC on HE or with an IHC pattern favoring SqCC were reassessed according to the criteria of the 2011-classification.

RESULTS

From the 336 cases 70% had a KRAS-mutation and 30% an EGFR-mutation. The number of cases with SqCC on HE and/or an IHC-profile favoring SqCC was 12. After the reassessment six specimens (1.8%) would not have been tested for EGFR-/KRAS-mutations, if the current diagnostic algorithm had been used: 2.0% of EGFR-mutations and 1.7% KRAS-mutations. All six cases were NSCLC with an IHC-profile favoring SqCC.

CONCLUSION

Most NSCLC-cases with EGFR- and KRAS-mutations are selected by the current diagnostic algorithm. As a small but relevant fraction is missed, there is room for improvement.

Minimum biopsy set for HER2 evaluation in gastric and gastro-esophageal junction cancer

BACKGROUND AND STUDY AIMS

The HER2 status of small endoscopic biopsies is important for predicting the eligibility of patients with metastatic HER2-positive gastric cancer or gastro-esophageal junction (GEJ) cancer for anti-HER2 therapy approved by the U.S. Food and Drug Administration. The aim of this study was to identify the minimum biopsy set required to evaluate the HER2 status with confidence.

PATIENTS AND METHODS

A total of 103 consecutive patients with resected gastric cancer or GEJ cancer were retrospectively selected; 2 formalin-fixed, paraffin-embedded samples of each surgical specimen and all paired endoscopic biopsies were analyzed for HER2 status with both immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) methods. A total of 10 virtual biopsies were constructed by selecting areas 2.6 mm in diameter on the luminal side of digitalized slides obtained from the surgical specimens. The results of evaluating HER2 status in virtual biopsies, slides containing complete surgical specimens, and endoscopic biopsies were compared. The resulting minimum biopsy set was applied to the endoscopic biopsy series for validation.

RESULTS

A biopsy set containing a minimum of 5 samples was identified as the most accurate in predicting HER2 status (sensitivity, 92 %; specificity, 97 %). In only 3 of the 103 cases (2.9 %) did a comparison of the HER2 evaluation of virtual biopsies and that of entire slides show inconsistent results. Overall agreement between the endoscopic biopsies and surgical samples for HER2 IHC status increased from 78.4 % to 92.3 % when biopsy sets containing 4 or fewer samples were compared with biopsy sets containing 5 or more samples.

CONCLUSIONS

Although the recommendations suggest that 8 to 10 biopsies are necessary, the results show that a minimum set of 5 biopsies may be sufficient for reliable HER2 assessment in gastric cancer and GEJ cancer. However, endoscopists should be aware that a smaller sample size may be less accurate in selecting patients eligible for anti-HER2 therapy.

HER2 in solid tumors: more than 10 years under the microscope; where are we now?

HER2 is a well-recognized mediator of the cancerogenic process. It is dysregulated in a wide range of solid tumors, mainly via protein overexpression and/or gene amplification, thus making HER2 an attractive target for tailored treatment. The anti-HER2 therapy trastuzumab was approved for the treatment of HER2-positive metastatic breast cancer patients more than 10 years ago. Since then, trastuzumab and other HER2-inhibitors have been entered into clinical practice for the treatment of breast cancer and, more recently, have been approved to treat HER2-positive metastatic gastric cancers. Currently, HER2-targeted therapies are under evaluation in other tumor types. Due to the relevance of proper patient selection, the accurate assessment of HER2 status is fundamental. This review will discuss the established knowledge and novel insights into the HER2 story, mainly focusing on breast, gastric and colorectal cancers, as well as providing a brief overview of salivary gland, bladder, ovarian and lung tumors.

Tumor profiling of gastric and esophageal carcinoma reveal different treatment options

BACKGROUND

NCCN states that chemotherapies for advanced esophageal and gastric cancers may be used interchangeably. Biomarkers from gastroesophageal cancer patients were interrogated to identify actionable alterations with therapeutic implications.

METHODS

666 gastric and 640 esophageal cancer cases referred to Caris Life Sciences between 2009 thru 2013 were evaluated. Specific testing was performed, which included a combination of sequencing (Sanger, NGS) and protein expression (IHC).

RESULTS

In the complete cohort (n = 1306), 30 of 45 genes tested harbored mutations; highest rates were seen in TP53 (54%), APC (10%), SMAD4 (5.9%), KRAS (5.9%), and PIK3CA (5.1%). IHC of TOP2A was high in 76% of cases, TOPO1 in 51% and SPARC in 25%; low IHC of ERCC1 was seen in 65%, RRM1 in 62%, TS in 61% and MGMT in 45%, indicating potential benefit from epirubicin, irinotecan, nab-paclitaxel, platinum-based agents, gemcitabine, 5FU/capecitabine and temozolomide, respectively. In the HER2+ cohort (n = 88), 50% of patients demonstrated possible benefit from a combination of trastuzumab with 5FU/capecitabine based on concurrent low TS, 53% with irinotecan (high TOPO1), 63% with cisplatin (low ERCC1) and 55% with gemcitabine (low RRM1). Subgroup analysis by tumor origin demonstrated significant differences in actionable biomarker profiles with HER2 (13% vs. 4.6%), SPARC (34% vs. 15%), TOP2A (86% vs. 67%), and TOPO1 (55% vs. 46%) in esophageal and gastric adenocarcinoma cases respectively (P < 0.05).

CONCLUSION

A comprehensive multiplatform biomarker analysis suggested significant biomarker differences between gastric and esophageal cancers. These results can assist in the development of future clinical trials.

Clinical significance of assessing Her2/neu expression in gastric cancer with dual tumor tissue paraffin blocks

One paraffin block is routinely used for human epidermal growth factor receptor 2 (Her2/neu) immunohistochemistry (IHC) assessment. Here, we investigated if picking 2 paraffin blocks for Her2/neu evaluation on 1 slide is an economical, efficient, and practical method, which may reduce false negativity of Her2/neu IHC assessment due to intratumoral heterogeneity. A total of 251 gastric cancer (GC) patients were divided into a cohort using 1 tumor tissue paraffin block (single-block group, n = 132) and a cohort using dual tumor tissue paraffin blocks (dual-block group, n = 119) when evaluating Her2/neu expression status by IHC. In dual-block group, we combined the results from 2 different paraffin blocks and used the higher one as the final score. The number of IHC 1+, 2+, and 3+ specimens in the single-block group was 31 (23.5%), 40 (30.3%), and 19 (14.4%), respectively. The combined final IHC score in the dual-block group of 1+, 2+, and 3+ was 26 (21.8%), 34 (28.6%), and 23 (19.3%), respectively. Inconsistent Her2/neu expression between blocks was found in 36 (30.3%) cases in the dual-block group. The pooled data in the single-block group and the dual-block group indicated that, when using dual blocks, the Her2/neu-positive (3+) rate of GC was higher compared to that in the single-block group. Our results implied that using dual paraffin blocks to assess Her2/neu expression of GC may help identify more patients with Her2/neu-positive GC who could benefit from targeted therapy, by reducing false-negative rate of Her2 status assessment. This is an efficient, economical, and practical method for Her2/neu evaluation of GC.

Efficacy and safety of trastuzumab in combination with oxaliplatin and fluorouracil-based chemotherapy for patients with HER2-positive metastatic gastric and gastro-oesophageal junction adenocarcinoma patients: a retrospective study

BACKGROUND

Trastuzumab with 5-fluorouracil (5-FU) and cisplatin offers prolonged survival in patients with HER2-overexpressing advanced gastric cancer (AGC) and advanced gastro-oesophageal junction cancer (AGOJ). Oxaliplatin in combination with intravenous 5-FU plus leucovorin (LV; modified [m]FOLFOX6) or capecitabine (XELOX) improves tolerability compared with 5-FU/cisplatin regimen. There are few data available on the efficacy and safety of trastuzumab-oxaliplatin-based chemotherapy in previously untreated HER2-positive AGC and AGOJ patients.

METHODS

Clinical data were retrospectively analysed in patients receiving trastuzumab plus mFOLFOX6 or XELOX as first-line therapy between July 2009 and December 2012. Eligible patients had histologically proven AGC or AGOJ, HER2 overexpression, and no prior chemotherapy for metastatic disease.

RESULTS

Thirty-four patients met the eligibility criteria. Median age was 63 years, 79% of patients had ECOG PS score of 0-1, and all had metastatic disease. Median duration of treatment was 7.5 months. Overall response rate was 41% (95% CI: 25-56). Median progression-free survival and overall survival were 9.0 months (95% CI: 5.6-12) and 17.3 months (95% CI: 13.5-32.3), respectively. Tolerability was acceptable. The most frequent grade 3-4 toxicities were neutropenia (8.8%) and neuropathy (17.6%).

CONCLUSION

mFOLFOX6-trastuzumab combination is an efficient regimen with an acceptable safety profile for AGC and AGOJ patients. These results warrant further prospective study.

HER2 expression status in diverse cancers: review of results from 37,992 patients

Human epidermal growth factor receptor 2 (HER2) amplification/overexpression is an effective therapeutic target in breast and gastric cancer. Although HER2 positivity has been reported in other malignancies, previous studies generally focused on one cancer type, making it challenging to compare HER2 positivity across studies/malignancies. Herein, we examined 37,992 patient samples for HER2 expression (+/- amplification) in a single laboratory. All 37,992 patients were tested by immunohistochemistry (IHC); 21,642 of them were also examined for HER2 amplification with either fluorescent in situ hybridization (FISH) (11,670 patients) or chromogenic in situ hybridization (CISH) (9,972 patients); 18,262 patients had tumors other than breast or gastric cancer. All tissues were analyzed in a Clinical Laboratory Improvement Amendments (CLIA) laboratory (Caris Life Sciences) at the request of referring physicians. HER2 protein overexpression was found in 2.7 % of samples. Over-expressed HER2 was detected predominantly in malignancies of epithelial origin; for cancers derived from mesenchyme, neuroendocrine tissue, central nervous system, and kidney, HER2 expression and amplification were remarkably rare or non-existent. Bladder carcinomas, gallbladder, extrahepatic cholangiocarcinomas, cervical, uterine, and testicular cancers showed HER2 positivity rates of 12.4, 9.8, 6.3, 3.9, 3.0, and 2.4 %, respectively. HER2 overexpression and/or amplification is frequently found across tumor types. These observations may have significant therapeutic implications in cancers not traditionally thought to benefit from anti-HER2 therapies.

Pathologic diagnostics of HER2 positivity in gastroesophageal adenocarcinoma

OBJECTIVES

The human epidermal growth factor receptor 2 (HER2) oncogene shows overexpression in 15% to 30% of gastroesophageal adenocarcinomas. Targeted anti-HER2 therapy with trastuzumab has been recently validated in advanced gastric and gastroesophageal junction cancer treatment. A standardized modified scoring system was recently introduced for gastroesophageal HER2 scoring. We aimed to validate this scoring system, including an analysis of interobserver variability of immunohistochemistry (IHC) scoring.

METHODS

In total, 323 patients with histologically confirmed invasive gastric or esophageal adenocarcinoma were examined for HER2 by IHC and chromogenic in situ hybridization (CISH). IHC 3 + or IHC 2 +/CISH positive tumors were considered HER2 positive. Interobserver variability on IHC scoring using the currently standard modified HER2 scoring system was determined among three clinical pathologists. Clinicopathologic characteristics were retrospectively retrieved from the patient records.

RESULTS

HER2 positivity was found in 50 (15.5%) of 323 patients. Interobserver agreement on IHC scoring was high (κ = 0.78). Most disagreement was found in diffuse or mixed tumor types and in weak to moderate stained samples (IHC 2 +). The HER2 IHC scoring system is sensitive in differentiating HER2 status before ISH.

CONCLUSIONS

The currently used standardized HER2 scoring system is an excellent, clinically applicable method to establish HER2 status in appropriately educated and trained pathologists.

Recent advances in the HER2 targeted therapy of gastric cancer

Recent advances in molecular targeted therapies, including targeting human epidermal growth factor receptor 2 (HER2), had a major forward step in the therapy for gastric cancer patients. Application of HER2-targeted therapies, in particular trastuzumab in combination with chemotherapy in metastatic HER2-positive gastric cancers, resulted in improvements in response rates, time to progression and overall survival. Nevertheless, as with breast cancer, many patients with gastric cancer develop resistance to trastuzumab. Several promising therapies are currently being developed in combination with chemotherapy to increase the efficacy and overcome the cancer-resistance. Here we review the current overview of clinical application of agents targeting HER2 in gastric cancer. We also discuss the ongoing trials supporting the use of HER2-targeted agents combined with cytotoxic agents or other monoclonal antibodies.

HER2 assessment by silver in situ hybridization: where are we now?

HER2 testing in breast and gastric cancer is critical not only as a prognostic tool but also as a predictive marker for response to the humanized monoclonal antibody trastuzumab. Currently, HER2 status is assessed on histological and cytological specimens by conventional validated methods such as immunohistochemistry and FISH, while bright-field in situ hybridization techniques, such as silver in situ hybridization and chromogenic in situ hybridization, may offer performance benefits over FISH. The major points are first, technical issues, advantages and disadvantages relevant to each methods, and their clinical implications and second, the well-known genetic heterogeneity of HER2, and the occurrence of polysomy of chromosome 17. This review aims to summarize the growing body of literature on the accuracy of bright-field in situ techniques, notably silver in situ hybridization, in assessing HER2 status, and to discuss the role of such methods in pathology practice.

HER2 screening data from ToGA: targeting HER2 in gastric and gastroesophageal junction cancer

BACKGROUND

In the Trastuzumab for GAstric cancer (ToGA) study, trastuzumab plus chemotherapy improved median overall survival by 2.7 months in patients with human epidermal growth factor receptor 2 (HER2)-positive [immunohistochemistry (IHC) 3+/fluorescence in situ hybridization-positive] gastric/gastroesophageal junction cancer compared with chemotherapy alone (hazard ratio 0.74). Post hoc exploratory analyses in patients expressing higher HER2 levels (IHC 2+/fluorescence in situ hybridization-positive or IHC 3+) demonstrated a 4.2-month improvement in median overall survival with trastuzumab (hazard ratio 0.65). The ToGA study provides the largest screening dataset available on HER2 overexpression/amplification in this indication. We further analyzed correlation(s) of HER2 overexpression/amplification with clinical and epidemiological factors.

METHODS

HER2-positivity was analyzed by histological subtype, tumor location, geographic region, and specimen type. Exploratory efficacy analyses were performed.

RESULTS

The HER2-positivity rate was 22.1 % across analyzed tumor samples. Rates were similar between European and Asian patients (23.6 % vs. 23.9 %), but higher in intestinal- vs. diffuse-type (31.8 % vs. 6.1 %), and gastroesophageal junction cancer versus gastric tumors (32.2 % vs. 21.4 %). Across all IHC scores, variability in HER2 staining (≤30 % stained cells) was observed in almost 50 % of cases, with increasing rates in lower IHC categories, and did not affect treatment outcome. The polysomy rate was 4 %.

CONCLUSIONS

HER2 expression varies by tumor location and type. All patients with advanced gastric or gastroesophageal junction cancer should be tested for HER2 status, preferably using IHC initially. Due to the unique characteristics of gastric cancer, specific testing/scoring guidelines should be adhered to.

Reproducibility of Her2/neu scoring in gastric cancer and assessment of the 10% cut-off rule

The application of Trastuzumab on gastric cancer patients is based on Her2/neu immunostaining. The testing method relies on visual estimation of both membranous staining intensity, and positive tumor ratio with respect to a 10% cutoff. We evaluated the effect of inter- and intraobserver variations of both factors on therapeutic decision, especially if the positive tumor ratio hovers around the 10% cutoff. Ten pathologists scored 12 Her2/neu immunohistologically stained whole sections of gastric cancer. Applying the common rules for Her2/neu testing for gastric cancer, they separately noted the strongest identifiable staining intensity and the corresponding positive tumor ratio. Scoring was done repeatedly using the microscope, plain virtual microscopy, and virtual microscopy with a manual outline drawing function. Agreements on the strongest identified staining intensities were moderate. Overall concordance correlation coefficients of positive tumor ratios ranged from 0.55 to 0.81. Reproducibility was not improved by virtual microscopy. Pathologists have a good ability to estimate ratios of clearly demarcated areas, but gradients in staining intensities hinder reproducible visual demarcation of positive tumor areas. When hovering around the 10% positive tumor ratio cutoff there is a risk of misinterpretation of the staining results. This could lead to a denial of Trastuzumab therapy. Assessment of Her2/neu expression should be carried out by experienced pathologists because they can more reproducibly rate membranous staining intensities. The low reproducibility of positive tumor ratio is inherent in the testing method and cannot be improved by virtual microscopy. Therefore, we propose to reconsider the 10% cut-off limit.

Oncogenic alterations in ERBB2/HER2 represent potential therapeutic targets across tumors from diverse anatomic sites of origin

BACKGROUND

Targeted ERBB2/HER2 inhibitors are approved by the U.S. Food and Drug Administration for the treatment of breast, gastric, and esophageal cancers that overexpress or amplify HER2/ERBB2, as measured by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), respectively. Activating mutations in ERBB2 have also been reported and are predicted to confer sensitivity to these targeted agents. Testing for these mutations is not performed routinely, and FISH and IHC are not applied outside of these approved indications.

MATERIALS AND METHODS

We explored the spectrum of activating ERBB2 alterations across a collection of ∼ 7,300 solid tumor specimens that underwent comprehensive genomic profiling using next-generation sequencing. Results were analyzed for base substitutions, insertions and deletions, select rearrangements, and copy number changes.

RESULTS

Known oncogenic ERBB2 alterations were identified in tumors derived from 27 tissues, and ERBB2 amplification in breast, gastric, and gastroesophageal cancers accounted for only 30% of these alterations. Activating mutations in ERBB2 were identified in 131 samples (32.5%); amplification was observed in 246 samples (61%). Two samples (0.5%) harbored an ERBB2 rearrangement. Ten samples (2.5%) harbored multiple ERBB2 mutations, yet mutations and amplifications were mutually exclusive in 91% of mutated cases.

CONCLUSION

Standard slide-based tests for overexpression or amplification of ERBB2 would fail to detect the majority of activating mutations that occur overwhelmingly in the absence of copy number changes. Compared with current clinical standards, comprehensive genomic profiling of a more diverse set of tumor types may identify ∼ 3.5 times the number of patients who may benefit from ERBB2-targeted therapy.

Oncogenic alterations in ERBB2/HER2 represent potential therapeutic targets across tumors from diverse anatomic sites of origin

BACKGROUND

Targeted ERBB2/HER2 inhibitors are approved by the U.S. Food and Drug Administration for the treatment of breast, gastric, and esophageal cancers that overexpress or amplify HER2/ERBB2, as measured by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), respectively. Activating mutations in ERBB2 have also been reported and are predicted to confer sensitivity to these targeted agents. Testing for these mutations is not performed routinely, and FISH and IHC are not applied outside of these approved indications.

MATERIALS AND METHODS

We explored the spectrum of activating ERBB2 alterations across a collection of ∼ 7,300 solid tumor specimens that underwent comprehensive genomic profiling using next-generation sequencing. Results were analyzed for base substitutions, insertions and deletions, select rearrangements, and copy number changes.

RESULTS

Known oncogenic ERBB2 alterations were identified in tumors derived from 27 tissues, and ERBB2 amplification in breast, gastric, and gastroesophageal cancers accounted for only 30% of these alterations. Activating mutations in ERBB2 were identified in 131 samples (32.5%); amplification was observed in 246 samples (61%). Two samples (0.5%) harbored an ERBB2 rearrangement. Ten samples (2.5%) harbored multiple ERBB2 mutations, yet mutations and amplifications were mutually exclusive in 91% of mutated cases.

CONCLUSION

Standard slide-based tests for overexpression or amplification of ERBB2 would fail to detect the majority of activating mutations that occur overwhelmingly in the absence of copy number changes. Compared with current clinical standards, comprehensive genomic profiling of a more diverse set of tumor types may identify ∼ 3.5 times the number of patients who may benefit from ERBB2-targeted therapy.

Discordance rate of HER2 status in primary gastric carcinomas and synchronous lymph node metastases: a multicenter retrospective analysis

Background: The assessment of human epidermal growth factor receptor 2 (HER2) gene amplification is essential in order to identify those patients affected by advanced gastric cancer who may benefit from Trastuzumab targeted therapy. Materials and Methods: With the aim to investigate the concordance rate in HER2 status between primary gastric carcinoma (GC) and synchronous lymphnode metastases, we investigated HER2 status in a cohort of 108 surgical formalin-fixed paraffin-embedded specimens of GC and matched synchronous metastatic lymph nodes collected from three different units of Anatomic Pathology in southern of Italy. Fleiss-Cohen weighted k statistics were used to assess the concordance rate of HER2 status. Results: HER2 amplification was observed in 17% of primary GCs and the overall concordance rate with corresponding nodal metastases was 90.74%. Changes in HER2 status between primary GC and matched synchronous metastases were evidenced in 10 (9.26%) cases. Of these, 6 cases were HER2 amplified in the primary GC and not amplified in the metastases, while 4 were HER2 not amplified in the primary tumour and amplified in the lymph node metastases. Conclusions: Although at present the simultaneous determination of HER2 in advanced gastric cancer and corresponding metastatic lymph nodes is not mandatory, the possibility that the synchronous metastases of GC have a different HER2 status from that of the primary tumour is of remarkable significance; Indeed this may have influence on the therapeutic management and prognosis of the patients.

High specificity but low sensitivity of mutation-specific antibodies against EGFR mutations in non-small-cell lung cancer

Determination of epidermal growth factor receptor (EGFR) mutations has a pivotal impact on treatment of non-small-cell lung cancer (NSCLC). A standardized test has not yet been approved. So far, Sanger DNA sequencing has been widely used. Its rather low sensitivity has led to the development of more sensitive methods including real-time PCR (RT-PCR). Immunohistochemistry with mutation-specific antibodies might be a promising detection method. We evaluated 210 samples with NSCLC from an unselected Caucasian population. Extracted DNA was analyzed for EGFR mutations by RT-PCR (Therascreen EGFR PCR kit, Qiagen, UK; reference method). For immunohistochemistry, antibodies against exon19 deletions (clone 6B6), exon21 mutations (clone 43B2) from Cell Signaling Technology (Boston, USA) and EGFR variantIII (clone 218C9) from Dako (Copenhagen, DK) were applied. Protein expression was evaluated, and staining score (multipum of intensity (graded 0-3) and percentages (0-100%) of stained tumor cells) was calculated. Positivity was defined as staining score >0. Specificity of exon19 antibody was 98.8% (95% confidence interval=95.9-99.9%) and of exon21 antibody 97.8% (95% confidence interval=94.4-99.4%). Sensitivity of exon19 antibody was 63.2% (95% confidence interval=38.4-83.7%) and of exon21 antibody was 80.0% (95% confidence interval=44.4-97.5%). Seven exon19 and four exon21 mutations were false negatives (immunohistochemistry negative, RT-PCR positive). Two exon19 and three exon21 mutations were false positive (immunohistochemistry positive, RT-PCR negative). One false positive exon21 mutation had staining score 300. The EGFR variantIII antibody showed no correlation to EGFR mutation status determined by RT-PCR or to EGFR immunohistochemistry. High specificity of the mutation-specific antibodies was demonstrated. However, sensitivity was low, especially for exon19 deletions, and thus these antibodies cannot yet be used as screening method for EGFR mutations in NSCLC. Refinement of sensitivity for the mutation-specific antibodies is warranted to improve molecular diagnosis using EGFR immunohistochemistry.

The advent of precision therapy in gastrointestinal malignancies: Targeting the human epidermal growth factor receptor family in colorectal and esophagogastric cancer

Until recently, systemic therapy for gastrointestinal malignancies was restricted to relatively noncancer-specific cytotoxic chemotherapy. Over the last 15 years targeted therapies have become available, most notably bevacizumab in the case of advanced colorectal cancer. Unfortunately, there are no predictive biomarkers to guide the use of this agent. In this review article, we describe the advent of “Precision Medicine” (in part, the use of patient-specific molecular markers to inform treatment) in gastrointestinal cancers: The use of monoclonal antibodies targeting epidermal growth factor receptor in advanced colorectal cancer, and human epidermal growth factor receptor 2-neu in advanced esophagogastric cancer. In both instances, biomarkers help in selecting appropriate patients for such treatment.

The relevance of external quality assessment for molecular testing for ALK positive non-small cell lung cancer: results from two pilot rounds show room for optimization

BACKGROUND AND PURPOSE

Molecular profiling should be performed on all advanced non-small cell lung cancer with non-squamous histology to allow treatment selection. Currently, this should include EGFR mutation testing and testing for ALK rearrangements. ROS1 is another emerging target. ALK rearrangement status is a critical biomarker to predict response to tyrosine kinase inhibitors such as crizotinib. To promote high quality testing in non-small cell lung cancer, the European Society of Pathology has introduced an external quality assessment scheme. This article summarizes the results of the first two pilot rounds organized in 2012-2013.

MATERIALS AND METHODS

Tissue microarray slides consisting of cell-lines and resection specimens were distributed with the request for routine ALK testing using IHC or FISH. Participation in ALK FISH testing included the interpretation of four digital FISH images.

RESULTS

Data from 173 different laboratories was obtained. Results demonstrate decreased error rates in the second round for both ALK FISH and ALK IHC, although the error rates were still high and the need for external quality assessment in laboratories performing ALK testing is evident. Error rates obtained by FISH were lower than by IHC. The lowest error rates were observed for the interpretation of digital FISH images.

CONCLUSION

There was a large variety in FISH enumeration practices. Based on the results from this study, recommendations for the methodology, analysis, interpretation and result reporting were issued. External quality assessment is a crucial element to improve the quality of molecular testing.

Molecular targeting to treat gastric cancer

Trastuzumab that targets human epidermal growth factor receptor 2 (HER2) protein is the only approved molecular targeting agent for treating gastric cancer in Japan and the outcomes have been favorable. However, trastuzumab is effective for only 10% to 20% of the population with gastric cancer that expresses HER2 protein. Molecular targeting therapy with bevacizumab against vascular endothelial growth factors (VEGF) and with cetuximab and panitumumab against the epidermal growth factors pathway that have been approved for treating colorectal cancer are not considered effective for treating gastric cancer according to several clinical trials. However, ramucirumab that targets VEGF receptor-2 prolonged overall survival in a large phase III clinical trial and it might be an effective molecular targeting therapy for gastric cancer. The significance of molecular targeting therapy for gastric cancer remains controversial. A large-scale randomized clinical trial of novel molecular targeting agents with which to treat gastric cancer is needed.

Biomarker testing for breast, lung, and gastroesophageal cancers at NCI designated cancer centers

BACKGROUND

Molecular biomarkers, a cornerstone of precision oncology, are critical in breast, gastroesophageal, and non-small cell lung cancer management (BC, GEC, NSCLC). Testing practices are intensely debated, impacting diagnostic quality and affecting pathologists, oncologists and patients. However, little is known about testing approaches used in practice. Our study described biomarker practices in BC, GEC, and NSCLC at the leading US cancer centers.

METHODS

We conducted a survey of the National Cancer Institute (NCI) designated centers on BC, GEC, and NSCLC biomarker testing. We used simple frequencies to describe practices, two-sided Fisher's exact test and two-sided McNemar's test for cross-cancer comparison. All statistical tests were two-sided.

RESULTS

For BC human epidermal growth factor receptor 2 (HER2), 39% of centers combine guidelines by using in situ hybridization (ISH) and immunohistochemistry (IHC) concurrently, and 21% reflex-test beyond guideline-recommended IHC2+. For GEC HER2, 44% use ISH and IHC concurrently, and 28% reflex-test beyond IHC2+. In NSCLC, the use of IHC is limited to 4% for epidermal growth factor receptor (EGFR) and 7% for anaplastic lymphoma kinase (ALK). 43.5% test NSCLC biomarkers on oncologist order; 34.5% run all biomarkers upfront, and 22% use a sequential protocol. NSCLC external testing is statistically significantly higher than BC (P < .0001) and GEC (P < .0001). NSCLC internally developed tests are statistically significantly more common than BC (P < .0001) and GEC (P < .0001).

CONCLUSIONS

At the NCI cancer centers, biomarker testing practices vary, but exceeding guidelines is a common practice for established biomarkers and emerging practice for newer biomarkers. Use of internally developed tests declines as biomarkers mature. Implementation of multibiomarker protocols is lagging. Our study represents a step toward developing a biomarker testing practice landscape.

Human epidermal growth factor receptor 2 testing in gastric cancer: recommendations of an Asia-Pacific task force

Human epidermal growth factor receptor 2 (HER2) testing in gastric and gastroesophageal junction cancer is an evolving area in clinical practice that has particular relevance to Asia-Pacific countries, which face a high incidence of these diseases. A growing body of evidence demonstrates that HER2-targeted therapy improves survival for patients with HER2-positive advanced disease, and drives the need for high-quality testing procedures to identify patients who will respond to treatment. However, various factors challenge day-to-day testing of gastric specimens in these countries, to a degree greater than that observed for breast specimens. Recommendations for HER2 testing of gastric cancer specimens were published as a result of the Trastuzumab for Gastric Cancer (ToGA) trial. The guidelines proposed in this manuscript build on these recommendations and emphasize local testing environments, particularly in Asia-Pacific countries. A multidisciplinary task force comprising experts from Asia-Pacific who actively work and provide education in the area was convened to assess the applicability of existing recommendations in the Asia-Pacific region. The resulting recommendations reported here highlight and clarify aspects of testing that are of particular relevance to the region, and notably emphasize multidisciplinary collaborations to optimize HER2 testing quality.

Human Epidermal Growth Factor Receptor 2 (HER2) in Cancers: Overexpression and Therapeutic Implications

Human epidermal growth factor receptor 2 (HER2) is a member of the epidermal growth factor receptor family having tyrosine kinase activity. Dimerization of the receptor results in the autophosphorylation of tyrosine residues within the cytoplasmic domain of the receptors and initiates a variety of signaling pathways leading to cell proliferation and tumorigenesis. Amplification or overexpression of HER2 occurs in approximately 15-30% of breast cancers and 10-30% of gastric/gastroesophageal cancers and serves as a prognostic and predictive biomarker. HER2 overexpression has also been seen in other cancers like ovary, endometrium, bladder, lung, colon, and head and neck. The introduction of HER2 directed therapies has dramatically influenced the outcome of patients with HER2 positive breast and gastric/gastroesophageal cancers; however, the results have been proved disappointing in other HER2 overexpressing cancers. This review discusses the role of HER2 in various cancers and therapeutic modalities available targeting HER2.

Prevalence and Clinical Outcomes for Patients With ALK-Positive Resected Stage I to III Adenocarcinoma: Results From the European Thoracic Oncology Platform Lungscape Project

Purpose

The prevalence of anaplastic lymphoma kinase (ALK) gene fusion (ALK positivity) in early-stage non–small-cell lung cancer (NSCLC) varies by population examined and detection method used. The Lungscape ALK project was designed to address the prevalence and prognostic impact of ALK positivity in resected lung adenocarcinoma in a primarily European population.

Methods

Analysis of ALK status was performed by immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) in tissue sections of 1,281 patients with adenocarcinoma in the European Thoracic Oncology Platform Lungscape iBiobank. Positive patients were matched with negative patients in a 1:2 ratio, both for IHC and for FISH testing. Testing was performed in 16 participating centers, using the same protocol after passing external quality assessment.

Results

Positive ALK IHC staining was present in 80 patients (prevalence of 6.2%; 95% CI, 4.9% to 7.6%). Of these, 28 patients were ALK FISH positive, corresponding to a lower bound for the prevalence of FISH positivity of 2.2%. FISH specificity was 100%, and FISH sensitivity was 35.0% (95% CI, 24.7% to 46.5%), with a sensitivity value of 81.3% (95% CI, 63.6% to 92.8%) for IHC 2+/3+ patients. The hazard of death for FISH-positive patients was lower than for IHC-negative patients (P = .022). Multivariable models, adjusted for patient, tumor, and treatment characteristics, and matched cohort analysis confirmed that ALK FISH positivity is a predictor for better overall survival (OS).

Conclusion

In this large cohort of surgically resected lung adenocarcinomas, the prevalence of ALK positivity was 6.2% using IHC and at least 2.2% using FISH. A screening strategy based on IHC or H-score could be envisaged. ALK positivity (by either IHC or FISH) was related to better OS.

Image analysis of immunohistochemistry is superior to visual scoring as shown for patient outcome of esophageal adenocarcinoma

Quantification of protein expression based on immunohistochemistry (IHC) is an important step in clinical diagnoses and translational tissue-based research. Manual scoring systems are used in order to evaluate protein expression based on staining intensities and distribution patterns. However, visual scoring remains an inherently subjective approach. The aim of our study was to explore whether digital image analysis proves to be an alternative or even superior tool to quantify expression of membrane-bound proteins. We analyzed five membrane-binding biomarkers (HER2, EGFR, pEGFR, β-catenin, and E-cadherin) and performed IHC on tumor tissue microarrays from 153 esophageal adenocarcinomas patients from a single center study. The tissue cores were scored visually applying an established routine scoring system as well as by using digital image analysis obtaining a continuous spectrum of average staining intensity. Subsequently, we compared both assessments by survival analysis as an end point. There were no significant correlations with patient survival using visual scoring of β-catenin, E-cadherin, pEGFR, or HER2. In contrast, the results for digital image analysis approach indicated that there were significant associations with disease-free survival for β-catenin, E-cadherin, pEGFR, and HER2 (P = 0.0125, P = 0.0014, P = 0.0299, and P = 0.0096, respectively). For EGFR, there was a greater association with patient survival when digital image analysis was used compared to when visual scoring was (visual: P = 0.0045, image analysis: P < 0.0001). The results of this study indicated that digital image analysis was superior to visual scoring. Digital image analysis is more sensitive and, therefore, better able to detect biological differences within the tissues with greater accuracy. This increased sensitivity improves the quality of quantification.

Accurate detection of BRAF p.V600E mutations in challenging melanoma specimens requires stringent immunohistochemistry scoring criteria or sensitive molecular assays

Malignant melanoma patients require BRAF mutation testing prior to initiating BRAF inhibitor therapy. Molecular testing remains the diagnostic gold standard, but recent work suggests that BRAF immunohistochemistry (IHC) confers comparable results. Sample attributes and scoring criteria that may affect BRAF IHC interpretation, however, are poorly defined. We investigated formalin-fixed, paraffin-embedded samples with variable challenging interpretative attributes: metastases, core needle biopsies, sample tissues less than 60 mm(2), samples with greater than 50% necrosis, and/or samples with greater than 10% melanin pigmentation. Three pathologists independently scored 122 BRAF V600E IHC-labeled melanoma samples for percentage (0%-100%) of staining intensity (0-3+). Interscorer BRAF IHC discrepancies were resolved by consensus review. Lenient (≥1+, >0%) and stringent (≥2+, ≥10%) IHC scoring criteria were compared to BRAF V600 mutation (cobas) results (n = 118). Specimens with greater than 10% melanin pigmentation and metastatic samples produced the majority of interobserver IHC and IHC/cobas scoring discrepancies. Consensus review using stringent scoring criteria decreased the number of discrepant results, yielded very good interobserver reproducibility, and improved specificity and positive predictive value for BRAF p.V600E detection. BRAF p.V600K mutations accounted for 57.1% of false-negative IHC results when stringent, consensus criteria scoring were used. The cobas test detected 75.0% (8/12) of BRAF IHC-negative BRAF p.V600K mutations confirmed by next-generation sequencing. Molecular BRAF testing is the preferred screening test for BRAF inhibitor therapy eligibility because of superior sensitivity in challenging interpretative melanoma specimens. However, BRAF V600E IHC has excellent specificity and positive predictive value when stringent, consensus scoring criteria are implemented. To decrease IHC scoring discrepancies, pathologists should interpret metastatic and pigmented samples with caution.

Comparison of HER2 status by fluorescence in situ hybridisation and immunohistochemistry in gastric cancer

AIM OF THE STUDY

To investigate the differences and relevance, and to evaluate the clinical significance of fluorescence in situ hybridisation and immunohistochemistry (IHC) in detecting HER2 in gastric cancer tissues.

MATERIAL AND METHODS

The expression of HER2 protein and the amplification of the HER2 gene in 118 gastric cancer tissues were detected by immunohistochemistry and fluorescence in situ hybridisation, respectively.

RESULTS

Using IHC, we found that in 40 cases (33.9%) the HER2 expression was at level 0, in 33 cases (28.0%) the HER2 expression was at level 1+, in 16 cases (14%) the HER2 expression was at level 2+, and in 29 cases (25.6%) the HER2 expression was at level 3+, respectively. Using the FISH test, 38 of 118 cases (32.2%) were judged as positive results. The concordance rate between the results of IHC and FISH in all cases was 85.6%. The concordance rate of IHC and FISH was high in cases of HER2 expression at level 0, 1+ and 3+ according to IHC, but low in cases of 2+ according to IHC (43.8%).

CONCLUSIONS

Immunohistochemistry cannot predict HER2 gene amplification accurately. The FISH test should be executed in IHC 2+ cases.

The validation of a novel method combining both HER2 immunohistochemistry and HER2 dual-colour silver in situ hybridization on one slide for gastric carcinoma testing

Background

HER2 status assessment is a prerequisite for the establishment of an appropriate treatment strategy in gastric cancer. Gastric cancers are very heterogeneous and separate evaluations of gene amplification and protein expression lead to uncertainties in localizing distinct clones and are time consuming. This study evaluates the equivalence of the novel method combining both gene and protein platforms on one slide.

Methods

Immunohistochemistry (IHC) and HER2 dual-colour silver in situ hybridization (SISH) as single methods (IHC/SISH) and gene-protein platform combining both methods on one slide (gene/protein) were performed in randomly collected 100 cases of gastric adenocarcinoma. Results of IHC/SISH were compared with gene/protein staining.

Results

96 of 100 samples were assessable. In the gene/protein staining, pathologists were able to assess gene amplification and consequent protein expression at the single cell level. In comparison trials, gene amplification was observed in 14.6% by both, conventional SISH and gene/protein platform (agreement 100%; Kappa-coefficient κ = 1.0). Protein expression scores by IHC were 70.8% (0), 10.4% (1+), 9.4% (2+), and 9.4% (3+). Protein expression by gene/protein method were: 70.8% (0), 11.5% (1+), 7.3% (2+) and 10.4% (3+) of patients. There were complete concordances in IHC assessment of cases with score 0 (100.0%; κ = 1). High concordances are shown in score 1+ (98.96%; κ = 0.947) and 3+ (96.88%; κ = 0.825) cases and good concordances in 2+ cases (95.83%; κ = 0.728).

Conclusions

This novel combined platform has the advantage of being able to evaluate both gene and the protein status in the same cancer cell and may be of particular interest for research and patient’s care.

Article category

Disease Biomarker.

Comparison of HER2 status between surgically resected specimens and matched biopsy specimens of gastric intestinal-type adenocarcinoma

HER2 protein overexpression and gene amplification are important biomarkers for identifying gastric cancer patients who may respond to HER2-targeted therapy using trastuzumab. The aim of this study was to evaluate the concordance between HER2 protein expression and gene amplification in both surgically resected tumors and matched biopsy specimens of gastric cancer. Formalin-fixed, paraffin-embedded sections of 207 surgically resected tumors and 158 biopsy specimens from 207 cases of invasive intestinal-type gastric cancer were analyzed. Protein expression was assessed using immunohistochemistry and graded by the modified scoring criteria for gastric cancer. Gene amplification was evaluated by fluorescence in situ hybridization (FISH). HER2 overexpression was observed in 17 % of both surgically resected tumors (35/207) and biopsy specimens (26/158). HER2 gene amplification was detected in 31 % (61/200) of surgically resected tumors and 32 % (47/147) of biopsy specimens. Except for immunohistochemistry (IHC) equivocal (2+) cases, the concordance rates between IHC and FISH was 90.9 % in surgically resected tumors and 90.2 % in biopsy specimens. In IHC 2+ cases, the rate of HER2 gene amplification was 56 and 38 % in surgically resected tumors and biopsy specimens, respectively. IHC-FISH discordance was mainly due to intratumoral heterogeneity and low-level gene amplification. The concordance rate of IHC results between surgically resected specimens and the corresponding biopsy specimen was 57.0 % (κ = 0.224), and in discordant cases, HER2 positivity in biopsies and HER2 negativity in surgically resected tumors were most common. The concordance rate of FISH results between surgically resected tumors and biopsy specimens was 72.7 % (κ = 0.313). Polysomy 17 was detected in 5.5 and 7.5 % of surgically resected tumors and biopsy specimens and significantly correlated with IHC score, but polysomy 17 could explain one IHC score 3+ and FISH-negative tumor only. Although high concordance rates between HER2-protein expression and gene amplification were observed in both surgically resected tumors and biopsy specimens, the agreement levels were evaluated to be fair. Polysomy 17 was infrequent and seemed to have limited impact on gastric HER2 testing. Further investigations are required for an appropriate biopsy method to reduce false results of HER2 testing and to clarify the clinical significance of intratumoral heterogeneity in HER2 status.

A critical review of HER2-positive gastric cancer evaluation and treatment: from trastuzumab, and beyond

Identification of the importance of human epidermal growth factor receptor-2 (HER2) status, biomarker testing and the development of anti-HER2 treatments have changed the prognosis of breast and gastric cancers. The addition of trastuzumab to chemotherapy has improved outcomes for patients with HER2-positive metastatic adenocarcinoma of the stomach and gastroesophageal junction, but some relevant issues remain to be elucidated or will emerge with new drugs. This article reviews the current state of HER2 in gastric cancer focusing on diagnostic and anti-HER2 targeted treatment issues and the role of trastuzumab in localized disease, and its combination or integration with new therapies.

Activation of EGFR and ERBB2 by Helicobacter pylori results in survival of gastric epithelial cells with DNA damage

BACKGROUND & AIMS

The gastric cancer-causing pathogen Helicobacter pylori up-regulates spermine oxidase (SMOX) in gastric epithelial cells, causing oxidative stress-induced apoptosis and DNA damage. A subpopulation of SMOX(high) cells are resistant to apoptosis, despite their high levels of DNA damage. Because epidermal growth factor receptor (EGFR) activation can regulate apoptosis, we determined its role in SMOX-mediated effects.

METHODS

SMOX, apoptosis, and DNA damage were measured in gastric epithelial cells from H. pylori-infected Egfr(wa5) mice (which have attenuated EGFR activity), Egfr wild-type mice, or in infected cells incubated with EGFR inhibitors or deficient in EGFR. A phosphoproteomic analysis was performed. Two independent tissue microarrays containing each stage of disease, from gastritis to carcinoma, and gastric biopsy specimens from Colombian and Honduran cohorts were analyzed by immunohistochemistry.

RESULTS

SMOX expression and DNA damage were decreased, and apoptosis increased in H. pylori-infected Egfr(wa5) mice. H. pylori-infected cells with deletion or inhibition of EGFR had reduced levels of SMOX, DNA damage, and DNA damage(high) apoptosis(low) cells. Phosphoproteomic analysis showed increased EGFR and erythroblastic leukemia-associated viral oncogene B (ERBB)2 signaling. Immunoblot analysis showed the presence of a phosphorylated (p)EGFR-ERBB2 heterodimer and pERBB2; knockdown of ErbB2 facilitated apoptosis of DNA damage(high) apoptosis(low) cells. SMOX was increased in all stages of gastric disease, peaking in tissues with intestinal metaplasia, whereas pEGFR, pEGFR-ERBB2, and pERBB2 were increased predominantly in tissues showing gastritis or atrophic gastritis. Principal component analysis separated gastritis tissues from patients with cancer vs those without cancer. pEGFR, pEGFR-ERBB2, pERBB2, and SMOX were increased in gastric samples from patients whose disease progressed to intestinal metaplasia or dysplasia, compared with patients whose disease did not progress.

CONCLUSIONS

In an analysis of gastric tissues from mice and patients, we identified a molecular signature (based on levels of pEGFR, pERBB2, and SMOX) for the initiation of gastric carcinogenesis.

Tumor markers in colorectal cancer, gastric cancer and gastrointestinal stromal cancers: European group on tumor markers 2014 guidelines update

Biomarkers currently play an important role in the detection and management of patients with several different types of gastrointestinal cancer, especially colorectal, gastric, gastro-oesophageal junction (GOJ) adenocarcinomas and gastrointestinal stromal tumors (GISTs). The aim of this article is to provide updated and evidence-based guidelines for the use of biomarkers in the different gastrointestinal malignancies. Recommended biomarkers for colorectal cancer include an immunochemical-based fecal occult blood test in screening asymptomatic subjects ≥50 years of age for neoplasia, serial CEA levels in postoperative surveillance of stage II and III patients who may be candidates for surgical resection or systemic therapy in the event of distant metastasis occurring, K-RAS mutation status for identifying patients with advanced disease likely to benefit from anti-EGFR therapeutic antibodies and microsatellite instability testing as a first-line screen for subjects with Lynch syndrome. In advanced gastric or GOJ cancers, measurement of HER2 is recommended in selecting patients for treatment with trastuzumab. For patients with suspected GIST, determination of KIT protein should be used as a diagnostic aid, while KIT mutational analysis may be used for treatment planning in patients with diagnosed GISTs.

Multi-colour FISH in oesophageal adenocarcinoma-predictors of prognosis independent of stage and grade

BACKGROUND

Oesophageal adenocarcinoma or Barrett's adenocarcinoma (EAC) is increasing in incidence and stratification of prognosis might improve disease management. Multi-colour fluorescence in situ hybridisation (FISH) investigating ERBB2, MYC, CDKN2A and ZNF217 has recently shown promising results for the diagnosis of dysplasia and cancer using cytological samples.

METHODS

To identify markers of prognosis we targeted four selected gene loci using multi-colour FISH applied to a tissue microarray containing 130 EAC samples. Prognostic predictors (P1, P2, P3) based on genomic copy numbers of the four loci were statistically assessed to stratify patients according to overall survival in combination with clinical data.

RESULTS

The best stratification into favourable and unfavourable prognoses was shown by P1, percentage of cells with less than two ZNF217 signals; P2, percentage of cells with fewer ERBB2- than ZNF217 signals; and P3, overall ratio of ERBB2-/ZNF217 signals. Median survival times for P1 were 32 vs 73 months, 28 vs 73 months for P2; and 27 vs 65 months for P3. Regarding each tumour grade P2 subdivided patients into distinct prognostic groups independently within each grade, with different median survival times of at least 35 months.

CONCLUSIONS

Cell signal number of the ERBB2 and ZNF217 loci showed independence from tumour stage and differentiation grade. The prognostic value of multi-colour FISH-assays is applicable to EAC and is superior to single markers.

Expression of HER-2 in rectal cancers treated with preoperative radiotherapy: a potential biomarker predictive of metastasis

BACKGROUND

Evidence suggests HER-2 overexpression may be predictive of prognosis in colorectal cancer patients, though this remains controversial.

OBJECTIVES

This study was performed to assess the prognostic value of HER-2 expression in locally advanced rectal cancer patients after preoperative radiotherapy.

PATIENTS AND METHODS

HER-2 expression was evaluated based on immunohistochemical (IHC) staining of resected specimens from 142 mid-to-low rectal cancer patients. Fluorescence in situ hybridization (FISH) was performed to confirm HER-2 overexpression in samples with an IHC score of 2+. Tumor regression grading (TRG) of the primary tumors was determined semiquantitatively using a tumor regression grading scheme advocated in the AJCC Cancer Staging Manual 7 edition.

RESULTS

When the total staining intensity was evaluated, 106 samples (74.6%) showed barely-perceptible positivity (0-1+; HER-2--negative), 15 samples (10.6%) showed moderate positivity (2+) and 21 samples (14.8%) showed strong positivity (3+, HER-2 positive). FISH confirmed that 2 cases showing moderate HER-2 positivity (2+) overexpressed HER2. There was no significant difference between the HER-2 positive and -negative groups with respect to age, gender, TRG, TNM stage, downstaging status, lymphovascular invasion or tumor differentiation. A significant correlation was found between HER-2 overexpression and the incidence of distant metastasis (p = 0.005). Subgroup analysis revealed this correlation was not significant (p = 0.247) in the radiation-insensitive (TRG0-2) subgroup, whereas a significant correlation (p = 0.026) between HER-2 overexpression and distant metastasis was found in the radiation-resistant (TRG3) subgroup. Multivariate analysis identified ypN stage (OR = 0.473, p = 0.002)and overexpression of HER-2 (OR = 3.704, p = 0.008) as independent risk factors for distant metastasis. There was no correlation between HER-2 overexpression and disease-free survival or overall survival among the study population.

LIMITATIONS

We reported that HER-2 overexpression was correlated with distant metastasis in rectal cancer patients, especially in the radiation-insensitive group. However, there are certain limitations. First, this study was limited due to the fact that the number of rectal patients enrolled was only 142, which is relatively small. Second, HER-2 expression was measured by IHC with a positive ratio around 15%, which is fairly high according to the literature. Also, we collected the tissue samples preoperatively. It would be interesting to know the HER-2 expression levels pre- and postradiotherapy, as well as their correlation with local recurrence or distant metastasis. Finally, in rectal cancer patients, there is little information published on HER-2 and its role in tumor progression and metastasis. Therefore, we are pursuing the regulatory molecule underlined.

CONCLUSIONS

HER-2 is overexpressed in around 15% of rectal cancer patients who receive neoadjuvant radiotherapy. Moreover, HER-2 overexpression could be a predictive biomarker of distant metastasis in rectal cancer patients after preoperative radiotherapy, especially patients showing a poor response to neoadjuvant radiotherapy.

[Ways to personalized medicine for gastric cancer]

Gastric cancer is the fourth most common tumor and the second most common cause of cancer-related deaths in the world. Approximately 70 % of the patients already have lymph node metastases at the time of the diagnosis leading to a median overall survival time of 16.7 months. Complete resection of the primary tumor with D2 lymphadenectomy offers the only chance of cure in the early stages of the disease. Survival of more locally advanced gastric cancer was improved by the introduction of perioperative, adjuvant and palliative chemotherapy of gastric cancer; however, the identification of novel predictive and diagnostic targets is urgently needed. Our own studies on gastric cancer biology identified several putative tumor biologically relevant G-protein-coupled receptors (e.g. AT1R, AT2R, CXCR4, FZD7, LGR4, LGR5, LGR6). Some of these receptors are also putative stem cell markers and may serve as future targets of an individualized therapy of gastric cancer.

EGFR, HER2 and HER3 dimerization patterns guide targeted inhibition in two histotypes of esophageal cancer

Receptor tyrosine kinases (RTKs) are in the focus of targeted therapy for epithelial tumors. Our study addressed the role of EGFR, HER2 and HER3 expression and dimerization in esophageal cancers in situ and in vitro in the context of therapeutic EGFR and HER2 inhibitors. In archival pretreatment biopsies of esophageal carcinomas (n = 110), EGFR was preferentially expressed in esophageal squamous cell carcinomas (ESCCs) (22.4%; p = 0.088) and HER2 (34.4%; p < 0.001) with HER3 (91.5%; p < 0.001) in esophageal (Barrett's) adenocarcinomas (EACs). In situ proximity ligation assays revealed mainly EGFR and HER2 homodimers in ESCC and EAC cases, respectively. However, EAC cases also exhibited HER2/HER3 heterodimers. In vitro ESCC (OE21) cells displayed a significant response to erlotinib, gefitinib and lapatinib, with loss of AKT phosphorylation, G0/G1 cell cycle arrest and induction of apoptosis. In EAC cells (OE19, OE33 and SK-GT-4), lapatinib was similarly effective in strongly HER2-positive (mainly HER2 homodimers and some HER2/EGFR heterodimers) OE19 and OE33 cells. The HER2-targeting antibodies (trastuzumab and pertuzumab) given alone were largely ineffective in ESCC and EAC cells. However, both antibodies significantly induced antibody-dependent cellular cytotoxicity in EAC (OE19 and OE33) cells upon co-culture with peripheral blood mononuclear cells. The study reveals that overexpression of EGFR and HER2 predominantly results in homodimers in ESCCs and EACs, respectively. Still, some EACs also show HER2 dimerization plasticity, e.g., with HER3. Such RTK dimerization patterns affect responses to EGFR and HER2 targeting inhibitors in ESCC and EAC cells in vitro and hence may influence future prediction for particularly HER2-targeting inhibitors in EACs.

Lgr5 over-expression is positively related to the tumor progression and HER2 expression in stage pTNM IV colorectal cancer

Recent studies display that Leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5) appears to involve the initiation of colorectal cancer (CRC). However, its role in the progression of CRC is not clear at present. In the present study, the expression of Lgr5, HER2, VEGF, and Ki-67 was detected by immunohistochemistry in primary cancer tissue and the matched normal mucosa, metastatic lymph node and distant metastatic tissues in 42 CRC cases staged as pTNM IV. The correlation of Lgr5 over-expression with the CRC progression, survival time, and expression of HER2, VEGF, and Ki-67 was evaluated. Moreover, the Lgr5 expression at the invasive front or residual cancer cells around coagulation necrosis was compared with that at the center of CRC in 51 paraffin embedded tissues. The results revealed that Lgr5 over-expression was more frequently found in the metastatic tissues of both lymph nodes and distant area when compared with primary CRC tissue (P<0.05). Additionally, cancer cells in the invasive front and residual cancer cells around or among the coagulation necrosis presented stronger Lgr5 immunoreactivity than that at tumor center (P<0.05), and strong positive staining was often observed in tumor budding cells. While, HER2 over-expression was detected in 28.9% (IHC 3+) and 42.1% (IHC 3+/2+) of CRC patients, neither Lgr5 nor HER2 expression was significantly related to the prognosis of CRC patients, though there was a positive correlation between Lgr5 and HER2 (P<0.05) or Ki-67 expression (P<0.05). In conclusions, Lgr5 over-expression might involve the proliferation, invasion, and distant and regional metastasis of CRC cells, and has potential positive relation to HER2 expression.

Overexpression of the HER2/neu Gene: A New Therapeutic Possibility for Patients With Advanced Gallbladder Cancer

BACKGROUND

The HER2/neu gene is a proto-oncogene that can predict the response to treatment with trastuzumab, pertuzumab, and lapatinib. This study was conducted to determine the frequency of HER2/neu overexpression and to identify a subgroup of patients with gallbladder cancer who would benefit from targeted therapy.

METHODS

Patients with gallbladder cancer (n = 187; 165 women and 22 men) with a recorded follow-up of at least 5 years were included, along with control subjects (n = 75). An automated immunohistochemical technique was used with an anti-ErbB2 antibody. Scoring was conducted according to the CAP/ASCO (College of American Pathologists/American Society of Clinical Oncology) criteria for breast cancer.

RESULTS

Overexpression of HER2/neu was observed in 12.8% of the cases. Of those, 0% were mucosal, 14.3% muscular, 12.8% subserosal, and 10.6% serosal. In 20% of the cases, equivocal staining was observed. Overexpression was more frequent in the advanced cancers and in the better differentiated tumors (13.8% and 17.4%, respectively), but the difference was nonsignificant. The patients with overexpression of HER2/neu had a worse overall survival, when compared with those who had no expression at 5 years (34% vs. 41%).

CONCLUSION

This is the single largest study of HER2/neu expression in gallbladder cancer to use commonly accepted scoring criteria. The results indicate that HER2/neu overexpression occurred in 14% of the advanced gallbladder cancer cases. This subgroup may benefit from inhibitors of the HER2/neu pathway.

Prognostic significance of HER2 expression based on trastuzumab for gastric cancer (ToGA) criteria in gastric cancer: an updated meta-analysis

The prognostic significance of HER2 expression in patients with gastric cancer remains controversial, partially due to the significant heterogeneity of the approaches and criteria used for HER2 assessment among different studies. We therefore conducted a meta-analysis enrolling only studies defining HER2 status by trastuzumab for gastric cancer (ToGA) criteria. Published studies investigating the association between HER2 expression and survival were identified. Only publications that defined HER2 expression using ToGA criteria were enrolled. Meta-analyses were performed by Revman 5.2. Pooled hazard ratio (HR) and its 95 % confidence interval (CI) were calculated to evaluate the risk of disease. A total of 11 studies were enrolled in meta-analyses. Pooled data of nine studies using univariate analysis showed that HER2 expression is not associated with overall survival (OS; pooled HR, 0.97; 95 % CI, 0.84-1.12; P=0.63), which are maintained in six studies of multivariate analysis (pooled HR, 1.01; 95 % CI, 0.75-1.35; P=0.95). The Q statistic test for nine studies of univariate analysis and for six studies of multivariate analysis showed no and low heterogeneity (I (2)=22 % and P=0.25; I (2)=41 % and P=0.13, respectively). Furthermore, pooled data of four studies without heterogeneity (I (2)=0 %, P=0.74) showed that HER2 expression were not associated with relapse-free survival as well, with a pooled HR of 1.08 (95 % CI, 0.84-1.37; P=0.55) in patients with HER2 expression. In conclusion, this meta-analysis indicated that HER2 expression based on ToGA criteria is not related to the survival in patients with gastric cancer.

HER2 mRNA status contributes to the discrepancy between gene amplification and protein overexpression in gastric cancer

BACKGROUND

Human epidermal growth factor receptor 2 (HER2) is an important proto-oncogene of prognostic use in gastric cancer (GC). Fluorescence in-situ hybridization (FISH) and immunohistochemistry (IHC) are the main clinical methods of detection of HER2, but consistency between the methods is poor and the cause of the discrepancy is unclear.

AIM

To investigate the involvement of HER2 mRNA status in the disparity between gene amplification and protein overexpression.

METHODS

We investigated HER2 gene, mRNA, and protein profiles in gastric precancer and cancer tissues by use of the molecular approaches FISH, real-time polymerase chain reaction, and IHC. The relationships between HER2 and matrix metalloproteinase 9 (MMP9) and Smad7 expression were analyzed and the involvement of HER2 in the interaction between tumor cells and lymphocytes was investigated by coculturing GC cell lines with peripheral blood mononuclear cells (PBMCs).

RESULTS

HER2 protein expression was significantly increased in cancer compared with precancer (P = 0.003), and the corresponding mRNA levels were significantly lower in precancer and cancer tissues than in normal tissues (κ = 0.290, P = 0.025). HER2 mRNA levels were significantly higher in tumor than in peritumor tissue (P = 0.028), and were positively correlated with MMP9 and Smad7 mRNA levels in tumor tissues. HER2 mRNA expression in GC cell lines was increased by coculture with PBMCs.

CONCLUSIONS

Different HER2 mRNA profiles, possibly in relation to contact between tumor cells and lymphocytes, might help to explain the discrepancy between gene amplification and protein overexpression results.