Usefulness and limitation of multiple endoscopic biopsy sampling for epidermal growth factor receptor and c-erbB-2 testing in patients with gastric adenocarcinoma.
BACKGROUND
Our objective was to examine the utility of endoscopic biopsy specimens in judging the status of epidermal growth factor receptor (EGFR) and c-erbB-2 genes and proteins in the entire tumor.


METHODS
Endoscopic biopsy specimens and specimens of whole representative cut surfaces of corresponding surgically resected tumors were obtained from 14 patients with gastric carcinoma, and immunohistochemistry and fluorescence in situ hybridization were then performed to determine the protein expression and gene amplification profiles, respectively, of EGFR and c-erbB-2 in these biopsy and surgical specimens.


RESULTS
Among the eight endoscopic biopsy specimens obtained from three gastric carcinomas in which EGFR protein overexpression and gene amplification were judged to be positive in the corresponding surgically resected tissue specimens, EGFR overexpression was detected in three specimens (38%), but EGFR amplification was not detected (0%). Among the 19 endoscopic biopsy specimens obtained from five gastric carcinomas in which c-erbB-2 protein overexpression and gene amplification were judged to be positive in the corresponding surgically resected tissue specimens, c-erbB-2 overexpression and amplification (c-erbB-2/CEP17 ratio) were detected in 14 (74%) and 16 (84%) specimens, respectively. All three cases with EGFR overexpression and all five cases with c-erbB-2 overexpression showed intratumor heterogeneity with regard to their EGFR and c-erbB-2 status, respectively.


CONCLUSIONS
The c-erbB-2 status could be adequately assessed not only by examining surgically resected materials, but also by examining multiple endoscopic biopsy specimens. On the other hand, to assess the EGFR status accurately, the use of surgically resected samples appeared to be more reliable than the use of multiple endoscopic biopsy samples.
Kimura
Mikihiko
M
Department of Pathology II, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
Tsuda
Hitoshi
H
Morita
Daisaku
D
Shinto
Eiji
E
Tanimoto
Takao
T
Ichikura
Takashi
T
Mochizuki
Hidetaka
H
Matsubara
Osamu
O
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D001706:Biopsy / Q000379:methods; D066246:ErbB Receptors / Q000096:biosynthesis* / Q000235:genetics; D005743:Gastrectomy; D005773:Gastroscopy; D005784:Gene Amplification; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics; D013270:Stomach / Q000473:pathology*; D013274:Stomach Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery
D014408:Biomarkers, Tumor; D066246:ErbB Receptors; D018719:Erb-b2 Receptor Tyrosine Kinases