Comparative analysis of thymidylate synthase at the protein, mRNA, and DNA levels as prognostic markers in colorectal adenocarcinoma.
OBJECTIVE
To determine the best routinely available molecular methodology for assessing thymidylate synthase (TS) as a prognostic marker in colorectal adenocarcinoma, TS was examined at the protein, mRNA, and DNA levels. Direct comparison of these routinely available assays has not been systematically studied across a large colon cancer patient cohort with long-term follow-up.


METHODS
We studied 150 surgically resected colorectal adenocarcinoma patients who received postoperative 5-Fluorouracil (5-FU) chemotherapy. TS immuunohistochemistry and real-time quantitative RT-PCR and PCR genotyping on patient-matched tumor and normal tissues were performed.


RESULTS
Surprisingly, mRNA values in normal tissue varied from 0.11 to 62.0 and significantly correlated with mRNA values of matched tumor tissues. Although higher tumor/normal ratios of mRNA expression trended toward poorer patient survival, neither this nor TS immunohistochemistry results were statistically significant predictors. TS tumor genotype was generally concordant with matched normal tissues. Further, the 2R/3R genotype of 5'-TSER was significantly correlated with poorer patient survival (P = 0.0249) and was also an independent prognostic marker on multivariate analysis.


CONCLUSIONS
TS genotyping on paraffin-embedded fixed tissues proved to be the most useful method for prediction of outcome of 5-FU treatment in patients with colorectal adenocarcinoma.
Ren
Dan-Ni
DN
Department of Pathology, Yonsei University Wonju College of Medicine, Wonju, South Korea.
Kim
Ik-Yong
IY
Koh
Sang Baek
SB
Chang
Sei Jin
SJ
Eom
Minseob
M
Yi
Sang Yeop
SY
Seong
Seung Hoon
SH
Kim
Mi-Dong
MD
Bronner
Mary P
MP
Cho
Mee-Yon
MY
D000230:Adenocarcinoma / Q000235:genetics / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000378:metabolism; D017024:Chemotherapy, Adjuvant; D015179:Colorectal Neoplasms / Q000235:genetics / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D004247:DNA / Q000378:metabolism*; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D005838:Genotype; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013940:Thymidylate Synthase / Q000235:genetics* / Q000378:metabolism
D000964:Antimetabolites, Antineoplastic; D014408:Biomarkers, Tumor; D012333:RNA, Messenger; D004247:DNA; D013940:Thymidylate Synthase; D005472:Fluorouracil