ABSTRACT
The specific role of human epidermal growth factor receptor-2 (HER2) status in rectal cancers remains unclear. This study therefore aimed to explore clinicopathologic and molecular characteristics, and prognostic value of HER2-positivity in residual mid- and/or low-rectal cancers after preoperative chemoradiotherapy (CRT). Surgical specimens from 145 patients with residual rectal cancer after preoperative CRT between January 2006 and January 2011 were used to evaluate HER2 status. HER2 protein expression and gene amplification were determined using immunohistochemistry (IHC) and silver in situ hybridization (SISH) on whole tissue sections, respectively. Polymerase chain reaction was used to analyze molecular characteristics, including microsatellite instability (MSI) and mutations in KRAS exon 2 (codon 12 and 13) and BRAF V600E mutation. Of 139 eligible patients, 8 (5.8%) had HER2 overexpression (IHC 2+ and 3+) that was not associated with clinicopathologic characteristics and patient survival, except positive circumferential resection margin (CRM) (P = 0.012). SISH was performed on 24 patient samples with IHC 1+ (n = 16), 2+ (n = 6), and 3+ (n = 2). HER2 amplification was identified in 3 patients (2.2%); however, this was also associated with positive CRM (P = 0.009) but not survival (all P > 0.05). Moreover, HER2 overexpression and amplification had no relationship with KRAS or BRAF mutations, and MSI status (all P > 0.05). HER2 positivity was found in a minority of rectal cancer patients and was not significantly associated with clinicopathologic and molecular characteristics. Our findings can be helpful in understanding the clinicopathologic bases of HER2 status in rectal cancers.
Subject(s)
Adenocarcinoma/genetics , Adenocarcinoma/therapy , Biomarkers, Tumor/genetics , Chemoradiotherapy, Adjuvant , Gene Amplification , Neoadjuvant Therapy , Receptor, ErbB-2/genetics , Rectal Neoplasms/genetics , Rectal Neoplasms/therapy , Adenocarcinoma/enzymology , Adenocarcinoma/pathology , Adult , Aged , Aged, 80 and over , Disease-Free Survival , Female , Genetic Predisposition to Disease , Humans , Immunohistochemistry , In Situ Hybridization , Male , Microsatellite Instability , Middle Aged , Mutation , Neoplasm Staging , Neoplasm, Residual , Phenotype , Polymerase Chain Reaction , Predictive Value of Tests , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins p21(ras)/genetics , Rectal Neoplasms/enzymology , Rectal Neoplasms/pathology , Retrospective Studies , Risk Factors , Time Factors , Treatment OutcomeABSTRACT
BACKGROUND/AIMS: The superiority of endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) over EUS-guided fine needle aspiration (EUS-FNA) remains controversial. Given the lack of studies analyzing histologic specimens acquired from EUS-FNB or EUS-FNA, we compared the proportion of the histologic core obtained from both techniques. METHODS: A total of 58 consecutive patients with solid mass lesions were enrolled and randomly assigned to the EUS-FNA or EUS-FNB groups. The opposite needle was used after the failure of core tissue acquisition using the initial needle with up to three passes. Using computerized analyses of the scanned histologic slide, the overall area and the area of the histologic core portion in specimens obtained by the two techniques were compared. RESULTS: No significant differences were identified between the two groups with respect to demographic and clinical characteristics. Fewer needle passes were required to obtain core specimens in the FNB group (p<0.001). There were no differences in the proportion of histologic core (11.8%±19.5% vs 8.0%±11.1%, p=0.376) or in the diagnostic accuracy (80.6% vs 81.5%, p=0.935) between two groups. CONCLUSIONS: The proportion of histologic core and the diagnostic accuracy were comparable between the FNB and FNA groups. However, fewer needle passes were required to establish an accurate diagnosis in EUS-FNB.
