High expression of thymidylate synthase (TS) is allegedly associated with the chemoresistance to 5-fluorouracil (5-FU) in colorectal cancers. However, low TS expression does not necessarily imply ...chemosensitivity. Inactivation of p16 super(INK4a) correlates with poor prognosis in various cancers. We immunohistochemically evaluated the relationship between the expression of TS, p16 super(INK4a), CDK4 and cyclin D1 and the effect of 5-FU-based chemotherapy in colorectal cancers. After antigen retrieval, immunoperoxidase staining was performed on the paraffin-embedded, biopsy and surgical specimens of 37 advanced colorectal cancers preoperatively treated with peroral administration of 5-FU derivatives. As a control group, 31 colorectal cancers without preoperative treatment were analyzed. High TS expression was found in 23 (74%) of 31 tumors resected from histological non-responders and in 19 (61%) of 31 controls but in none of six responders. High p16 super(INK4a) expression was seen in 83% of the responders, 52% of the non-responders and 32% of the controls. The TS-low-p16 super(INK4a)-high phenotype was noted in 83% of the responders, but only in 3% of the non-responders (P = 0.0001). Induction of p16 super(INK4a) expression after chemotherapy was predominantly seen in the responders. Neither CDK4 nor cyclin D1 expression was related to the chemotherapeutic effects. In conclusion, the combination of low expression of TS and induction of p16 super(INK4a) after chemotherapy can be important indicators of the sensitivity to 5-FU-based chemotherapy in colorectal cancers.
The immunohistochemical expression of type 1 blood group antigens (type 1 BGAs) was analyzed for 30 cases of testicular germ cell tumors (TGCTs), using monoclonal antibodies against DU-PAN-2, CA19-9, ...Lewis(a) (Le(a)), and Lewis(b) (Le(b)). DU-PAN-2 was expressed very frequently in all of the embryonal carcinomas (ECs). CA19-9 expression was demonstrated in 53% of ECs, but the number of positive cells was generally smaller than that for DU-PAN-2. CA19-9-negative ECs tended to show a higher number of DU-PAN-2-positive cells compared to CA19-9-positive ECs, and ECs in which DU-PAN-2 was more strongly expressed showed a relatively frequent expression of CA19-9. In 36% of seminomas and 56% of yolk sac tumors (YSTs), DU-PAN-2 was weakly expressed, and the positive cells were few in number. Little or no expression of CA19-9 was demonstrated in seminomas and YSTs. Regarding Le(a) and Le(b), the expressions were found to be limited to teratomas at a frequency of 57% and 86%, respectively, with the exception of one EC positive for Lea and one YST positive for Leb. Eighty-six percent of teratomas showed expressions of DU-PAN-2 and CA19-9. DU-PAN-2 was also seen in some intratubular malignant germ cells. The antibodies used were all negative for choriocarcinomas, syncytiotrophoblastic giant cells, and normal testicular tissues. The antigen expressions were predominantly observed on the surface of tumor cells developing luminal structures. In conclusion, although CA19-9 was relatively specific for ECs, it should be emphasized that ECs were rather characteristic of extensive DU-PAN-2 expression. Particularly in CA19-9-negative ECs, a combined analysis of DU-PAN-2 and CA19-9 would be helpful in confirming the histopathologic diagnosis of TGCTs. The clinical significance of DU-PAN-2 in ECs as a tumor marker remains to be clarified. Le(a) and Le(b) expressions were thought to be related to the differentiation or maturation rather than to the malignant transformation in TGCTs.
Although orotate phosphoribosyltransferase (OPRT EC 2.4.2.10) is a key enzyme related to the first-step activation process of 5-fluorouracil, and therefore it has been shown to be an important enzyme ...that enables to predict sensitivity to 5-fluorouracil, the clinical and prognostic significance of protein and/or gene expression of OPRT has not been well established in gastric carcinoma. We examined the protein level, and mRNA expression of OPRT in gastric carcinoma tissues and relationships with clinicopathologic factors and prognosis were evaluated. A total of 75 surgically-resected gastric carcinoma tissues were subjected to the study. An enzymelinked immunosorbent assay (ELISA) was used to accurately assess intratumoral OPRT, and gene expressions of OPRT were examined using a real-time PCR method. Survival of patients with gastric carcinoma in relation to OPRT protein levels was analyzed using Kaplan-Meier methods along with log-rank test. The mean value of OPRT was 5.4+/-3.6 ng/mg protein, and it was significantly higher in patients with differentiated-type and invasive-type gastric carcinoma. The prognosis of patients in the high OPRT group was better than for those with low OPRT (p<0.05). There was a significant correlation between OPRT levels measured by ELISA and OPRT mRNA expression (p<0.05). Determination of OPRT levels is a useful tool to predict the biological characteristics of gastric carcinoma and possibly predict sensitivity to fluoropyrimidine-based anticancer chemotherapy,particularly dihydropyrimidine dehydrogenase-inhibitory fluoropyrimidine, in patients with gastric carcinoma.
Orotate phosphoribosyltransferase (OPRT EC 2.4.2.10) is a key enzyme related to the first-step phosphorylation process of 5-fluorouracil. We have recently developed an ELISA system to measure OPRT ...levels in cancerous tissues. We examined OPRT levels in 75 gastric carcinoma tissues using this ELISA, and the relationships with clinicopathologic factors were evaluated. A total of 75 surgically-resected gastric carcinoma tissues were subjected to the present study. The intratumoral OPRT level was determined by a newly-developed enzyme-linked immunosorbent assay (ELISA). Enzyme activities of OPRT were also determined using a conventional enzyme assay using radiolabeled 5-fluorouracil as a substrate. OPRT levels in gastric carcinoma tissues measured by ELISA were 5.4+/-3.6 ng/mg protein, ranging from 0.2 to 15.7 ng/mg protein. There was a significant correlation between the OPRT level measured by the ELISA and OPRT enzyme activity (y=0.545x - 0.017, r(2)=0.617, p<0.0001). OPRT levels were significantly higher in patients with differentiated type and invasive type of gastric carcinoma, whereas OPRT levels were not associated with the pathological stage of gastric carcinoma. These results suggest that OPRT levels were related to the histopathological characteristics of gastric carcinoma, and may be related to the response to fluoropyrimidine-based anticancer chemotherapy.
Previous studies have suggested that heat shock proteins (HSP) of Helicobacter pylori (H. pylori) are involved in the induction of autoimmunity mediated gastritis. In the present report, the ...cross‐reactivity between H. pylori‐related HSP60 and gastric epithelial cells was investigated by the indirect immunoperoxidase method using two monoclonal antibodies (mAb) against H. pylori‐derived HSP60, H9 and H20. H9 is reactive with an epitope common to bacterial HSP60, while H20 is specific to H. pylori HSP60. A total of 70 paraffin‐embedded gastric biopsy specimens were analyzed after heat‐induced epitope retrieval. Both mAb were cross‐reactive with the gastric epithelial cells, with a higher frequency seen for the H9‐reactive epitope. The frequency of positive epithelial decoration was not significantly different between H. pylori‐positive and H. pylori‐negative gastric mucosae. A variety of epithelial and non‐epithelial cells were immunostained with mAb H9, while mAb H20 was cross‐reactive only with small intestinal epithelia. Reactivity was mainly located in the Golgi area and rarely in the cytoplasm. These results suggest a noteworthy pitfall in immunohistochemical interpretations of HSP60‐associated autoimmune reactions in the gastric mucosa.
Previous studies have suggested that high expression of thymidylate synthase (TS) is involved in the resistance of cancer cells to 5-fluorouracil (5-FU) and its derivatives. In order to overcome ...the difficulty in identifying TS immunoreactivity in formalin-fixed, paraffin-embedded sections, we determined the most suitable and reproducible condition of antigen retrieval for TS localization. Antigen retrieval methods examined included 0.2% trypsin, 0.002% proteinase K, and pressure cooking in 10 mM citrate buffer, pH 6.0 and pH 7.0, and 1 mM EDTA (ethylenediaminetetraacetic acid) solution, pH 8.0. Pressure cooking with EDTA was the best choice for retrieving the antigenicity of TS. Polyclonal antibody was superior to monoclonal antibody TS106. Preabsorption test demonstrated the specificity of the immunostaining. The staining sequence using routine paraffin sections can contribute to the establishment of the prognostic indicator and optimal 5-FU dosage in a variety of 5-FU-sensitive or -insensitive malignancies.
High expression of thymidylate synthase (TS), p53 protein and bcl-XL protein has been suggested to be associated with chemoresistance of colorectal malignancies. The significance of TS, p53 protein ...and bcl-XL protein as predictive parameters of effects of 5-fluorouracil (5-FU)-based chemotherapy on colorectal cancers was evaluated. Immunoperoxidase staining of TS, p53 protein and bcl-XL protein was performed on formalin-fixed, paraffin-embedded, _??__??_opsied and resected specimens from 37 patients with advanced colorectal cancers, preoperatively treated with 5-FU derivatives per os. Suitable antigen retrieval was applied to the respective markers. Histologically, six tumors responded to the chemotherapy, while the remaining 31 tumors did not. Thirty-one control colorectal cancer cases without preoperative treatment were also analyzed. When more than one third of the cancer cells were stained, the lesions were considered high for antigen expression. High TS expression in the resected tumors was seen in 23 (74%) of 31 histologic non-responders but none in six responders. TS expression in preoperative biopsies and resected specimens was concordant in 80% of cases when two or more biopsy specimens were available. The rate of high TS expression was comparable in the control non-treated group. There was no difference between chemotherapeutic effects and the expression of p53 protein or bcl-XL protein. Chemoresistance to 5-FU and 5-FU derivatives can be predicted by immunohistochemical detection of high TS expression in biopsy samples. This provides us with a useful guide for preoperative selection of patients unresponsive to 5-FU-based chemotherapy. Expression of p53 protein and bcl-XL protein is unsatisfactory for predicting the 5-FU resistance.
Expression of type-1 carbohydrate antigens (CBAs), DU-PAN-2 and CA19-9, was strongly dependent on hormonal regulation during the menstrual cycle in the endometrium. DU-PAN-2 expression was more ...frequent than that of CA19-9 in endometrial adenocarcinomas (EMACs), with no correlation to menopausal status. The relationship between immunohistochemical profiles and serum values was statistically proven to be closer for DU-PAN-2 than for CA19-9. Although during staging-up the serological positive ratios distinctly increased for both DU-PAN-2 and CA19-9, the serum DU-PAN-2 values tended to decrease according to histological grading-up and the reverse was true for CA19-9. In the analysis of variable thyroid diseases, from the specific and frequent expression of DU-PAN-2 in papillary carcinomas, it was suggested that DU-PAN-2 would be a useful immunohistochemical marker for distinguishing papillary carcinomas from follicular tumors. For testicular germ cell tumors (TGCTs), it could be emphasized that embryonal carcinomas were rather characteristic of extensive DU-PAN-2 expression. Particularly in CA19-9-negative cases, a combined analysis would be helpful in confirming the histologic diagnosis of embryonal carcinoma. The biological significance of characteristic DU-PAN-2 expression as a tumor marker in the above tumors remains to be clarified. The difference in activity of the specific glycosyltransferases, α-2-3-sialyltransferase and α-1-4-fucosyltransferase, may result in the variable expression profiles of these antigens.
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