Overexpression of P-glycoprotein in untreated AFP-producing gastric carcinoma.
P-glycoprotein (P-gly), which is responsible for the phenotypic expression of multidrug resistance in cancerous tissue was stained immunohistochemically in previously untreated alpha-fetoprotein (AFP)-producing (n = 20) and nonproducing gastric cancers (n = 20). P-gly, AFP, and carcinoembryonic antigen(CEA) were stained in formalin-fixed paraffin-embedded tissue sections immunohistochemically using the monoclonal antibody JSB-1, anti-AFP, and anti-CEA, respectively. DNA ploidy pattern was determined by Fluorescence Activated Cell Sorter (FACS) analyzer. P-gly was significantly overexpressed in AFP producing gastric cancers (60%) than in AFP nonproducing ones (20%) (P < 0.01). When the result of P-gly staining was analyzed among the AFP-positive cases, P-gly positivity did not emerge either as a significant prognostic factor or as a predictor of the metastatic potentiality of the tumor. The intrinsic overexpression of P-gly in AFP producing gastric cancers proves its biological and morphological similarities to hepatocellular carcinoma. The significantly (P < 0.05) higher incidence of P-gly in diploid tumors indicate that expression of this phenotype might be related to the differentiation of the tumor. P-gly was overexpressed in AFP producing gastric carcinoma and the existing drug resistance, frequent recurrence, and poor prognosis might be explained by presence of P-gly in this carcinoma.
Dhar
D K
DK
Second Department of Surgery, Shimane Medical University, Izumo, Japan.
Nagasue
N
N
Yoshimura
H
H
Tachibana
M
M
Tahara
H
H
Matsuura
H
H
Abe
S
S
Chang
Y C
YC
Nakamura
T
T
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002272:Carcinoembryonic Antigen / Q000032:analysis; D002277:Carcinoma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D004273:DNA, Neoplasm / Q000032:analysis; D018432:Drug Resistance, Multiple; D005434:Flow Cytometry; D006801:Humans; D016612:Paraffin Embedding; D011379:Prognosis; D013194:Staining and Labeling; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D000509:alpha-Fetoproteins / Q000096:biosynthesis*
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002272:Carcinoembryonic Antigen; D004273:DNA, Neoplasm; D000509:alpha-Fetoproteins