Mayuko Saito

Serum HER2 as an adjunct to assess HER2 status for advanced gastric cancer: A prospective multicenter trial (SHERLOCK)

Abstract Background: Intratumoral human epidermal growth factor receptor 2 (HER2) heterogeneity of gastric cancer can be an obstacle to accurate HER2 assessment. Serum HER2, concentrations of the HER2 extracellular domain shed into the bloodstream, has a potential to compensate HER2 immunohistochemistry (IHC) but has not been scrutinized in gastric cancer. This study sought to explore the clinical utility of serum HER2 in gastric cancer. Methods: We performed a prospective multicenter trial (SHERLOCK trial) involving patients with all-stage gastric or gastro-esophageal junction cancer. Serum HER2 was measured using direct chemiluminescence while tissue HER2 status was determined using IHC and fluorescent in situ hybridization. For stage IV cases, concordance between local and central laboratories in tissue HER2 assessment was also evaluated. Results: Of 224 patients enrolled, both tissue HER2 status and serum HER2 levels were successfully determined in 212 patients and 21% (45/212) were tissue HER2-positive. Serum HER2 levels, ranged from 4.5 to 148.0 ng/ml (median 10.3), correlated with tissue HER2 status (p = 0.003). At a cut-off level of 28.0 ng/ml determined by receiver operating characteristics analysis, sensitivity, specificity, positive and negative predictive values of serum HER2 were 22.6%, 100%, 100% and 82.3%, respectively. All nine cases with elevated serum HER2 were tissue HER2-positive stage IV cases. Among 61 stage IV cases, the agreement rate for IHC scoring between the local and the central laboratories was 82% and tissue HER2 judgment was conflicting in five (8.2%) cases. Of these five cases, four were confirmed as false-negative and two of these four patients demonstrated elevated serum HER2. Conclusions: Serum HER2 levels correlated with tissue HER2 status in gastric cancer. Although the low sensitivity is a drawback, serum HER2 might be a useful adjunct tool to detect tissue HER2 false-negative gastric cancer.

Pharyngeal cancer surveillance using narrow band imaging during conventional upper gastrointestinal endoscopy.

Background: Recent studies have suggested that narrow band imaging (NBI) is useful for detecting superficial pharyngeal cancer. Nevertheless, pharyngeal observation is not a routine practice during upper gastrointestinal (GI) endoscopy. Two aims of this study were to evaluate the feasibility of pharyngeal observation during upper GI endoscopy and to determine the prevalence of pharyngeal cancer in asymptomatic high-risk patients. Methods: Fifty-year-old or older asymptomatic males with smoking and drinking habits were prospectively recruited as a pharyngeal cancer high-risk group. A total of 224 high-risk patients underwent pharyngeal observation using NBI before conventional upper GI endoscopy. The feasibility of pharyngeal examination without sedation was assessed by a questionnaire for the first 60 participants. Results: The median time for pharyngeal observation was 1.7 min. The questionnaire demonstrated 88% of participants thought the pharyngeal examination acceptable. The NBI examination identified 5 superficial pharyngeal cancers (2 Tis and 3 T1) in 224 high-risk patients; the prevalence of pharyngeal cancer in this group was 2.2%. Three of the 5 patients had a concurrent or past history of esophageal squamous cell carcinoma (ESCC). Conclusions: Pharyngeal observation using NBI during upper GI endoscopy is well tolerated and recommended for all high-risk patients, particularly those with a history of ESCC.

HER2-positive gastric cancer identified by serum HER2: A case report

Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are the current standards methods for the determination of tissue human epidermal growth factor receptor 2 (HER2) status in gastric cancer, as for breast cancer. However, HER2-positive gastric cancer occasionally exhibits heterogeneous tissue HER2 overexpression, raising concern regarding false-negative results in unresectable cases diagnosed by biopsy samples. Serum HER2, the concentration of the extracellular domain of HER2 protein shed into the bloodstream, has the potential to supplement the use of IHC or FISH to determine HER2 status. However, the clinical significance of serum HER2 has not been well studied in gastric cancer. The present study describes an illustrative case of metastatic gastric cancer initially diagnosed as HER2-negative (IHC score 1+). The patient exhibited an elevated serum HER2 level, which prompted a reevaluation of the tissue by IHC, using an alternative antibody, and FISH; re-biopsy analyses confirmed the case as HER2-positive, and trastuzumab was subsequently added to the combination chemotherapy with capecitabine and cisplatin. Serum HER2 may aid in avoiding false-negative diagnoses of HER2 gastric cancer.