Development and characterization of 1C6-203, a new monoclonal antibody specific to human thymidine phosphorylase.
Thymidine phosphorylase (dThdPase) is an essential enzyme for activation of the oral cytostatic drug capecitabine and its intermediate metabolite, doxifluridine, to 5-fluorouracil in tumors. Methods to estimate dThdPase expression in tumor tissue might be useful to predict the efficacy of capecitabine and doxifluridine in cancer patients. We established a new monoclonal antibody (MAb), 1C6-203, applicable for dThdPase immunohistochemistry and compared its staining characteristics with those of a previously established MAb, 654-1. In 4% paraformaldehyde-fixed colorectal carcinoma, 1C6-203 and 654-1 stained cancer cells in 19/30 and 9/30 patients, respectively. In 10% formalin-fixed colorectal carcinoma, 1C6-203 and 654-1 stained cancer cells in 18/30 and 6/30 patients, respectively. In negative 10% formalin-fixed tissues, microwave treatment improved the positivity of 654-1-stained cancer cells. These results suggest that an epitope recognized by 1C6-203 is resistant to epitope masking by formaldehyde fixation, whereas that for MAb 654-1 is sensitive. Therefore, MAb 1C6-203 might be more suitable than MAb 654-1 for evaluating dThdPase expression in colorectal carcinoma.
Kono
T
T
Second Department of Surgery and Medicine, Kamakura, Kanagawa, Japan. kono@asahikawa-med.ac.jp
Nishida
M
M
Inagaki
N
N
Tanaka
Y
Y
Yoneda
M
M
Kasai
S
S
D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis; D000918:Antibody Specificity; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000201:enzymology; D015179:Colorectal Neoplasms / Q000201:enzymology; D005260:Female; D005404:Fixatives; D005557:Formaldehyde; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D011108:Polymers; D013274:Stomach Neoplasms / Q000201:enzymology; D013939:Thymidine Phosphorylase / Q000276:immunology* / Q000378:metabolism; D016707:Tissue Fixation
D000911:Antibodies, Monoclonal; D005404:Fixatives; D011108:Polymers; D005557:Formaldehyde; D013939:Thymidine Phosphorylase; C003043:paraform