Characterization of dihydropyrimidine dehydrogenase on immunohistochemistry in colon carcinoma, and correlation between immunohistochemical score and protein level or messenger RNA expression.
BACKGROUND
Dihydropyrimidine dehydrogenase (DPD) is the first enzyme that metabolizes 5-fluorouracil (5-FU). Until now, enzymatic activity or mRNA expression of DPD has been investigated. However, there are no papers on immunohistochemical evaluation of DPD. We investigated DPD staining on immunohistochemistry, and examined the relationship among immunohistochemical score, protein level and mRNA expression of DPD.


METHODS
Forty-seven resected colon cancer specimens, four colon cancer cell lines, two xenografts by colon cancer cell lines, and human mononuclear cells were used. Immunohistochemistry was performed using DPD monoclonal antibody. Protein levels were determined by Western blot analysis. And mRNA levels were calculated by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR).


RESULTS
DPD was strongly expressed in the cytoplasm of cancer cells, and in the cytoplasm of macrophage and plasma cells. The immunohistochemical score was more correlated with protein levels (P = 0.0054) than mRNA expression (P = 0.9028).


CONCLUSIONS
We investigated the characterization of DPD immunohistochemically, and showed that immunohistochemical expression of DPD can be used to predict the sensitivity of colorectal carcinomas to 5-FU.
Takenoue
T
T
Department of Surgical Oncology, The University of Tokyo, Hongo, Japan. takenoue-1su@h.u-tokyo.ac.jp
Kitayama
J
J
Takei
Y
Y
Umetani
N
N
Matsuda
K
K
Nita
M E
ME
Hatano
K
K
Tsuruo
T
T
Nagawa
H
H
D000368:Aged; D000911:Antibodies, Monoclonal; D000964:Antimetabolites, Antineoplastic / Q000378:metabolism* / Q000627:therapeutic use; D001706:Biopsy; D015153:Blotting, Western; D003106:Colon / Q000737:chemistry / Q000378:metabolism; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D042943:Dihydrouracil Dehydrogenase (NADP); D005260:Female; D005472:Fluorouracil / Q000378:metabolism* / Q000627:therapeutic use; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D010088:Oxidoreductases / Q000032:analysis / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000911:Antibodies, Monoclonal; D000964:Antimetabolites, Antineoplastic; D012333:RNA, Messenger; D010088:Oxidoreductases; D042943:Dihydrouracil Dehydrogenase (NADP); D005472:Fluorouracil