Fatty acid binding protein 6 is overexpressed in colorectal cancer.

PURPOSE: Fatty acid binding protein 6 (FABP6) is a cancer-related protein that acts as an intracellular transporter of bile acid in the ileal epithelium. Because bile acids are implicated in the carcinogenesis of colorectal cancer, we evaluated FABP6 expression in colorectal cancer. EXPERIMENTAL DESIGN: The expression of FABP6 mRNA was evaluated in 78 paired samples of cancer/normal tissue representing colorectal cancer cases, plus 16 adenomas, and 16 metastatic lymph nodes. An immunohistochemical study was conducted with paraffin sections. In vitro transfection was done to determine FABP6's biological roles. RESULTS: The expression of FABP6 mRNA was significantly higher in cancer (75 of 78, 96.2%) than in normal tissue (P<0.001). The expression of mRNA was increased in cancer compared with adenoma, but was dramatically decreased in node metastases. Tumors with high FABP6 expression were smaller in size (P<0.01), more often in the left colon (P<0.05), and had shallower invasion into the bowel wall (P<0.05) compared with those with low expression. There was no significant difference between high- and low-expression tumors regarding clinicopathologic variables such as histologic type, lymph node, or liver metastasis, Dukes' classification, and prognosis. Immunohistochemical study revealed that FABP6 expression was primarily observed in cancer cells. In vitro transfection revealed that transfectants showed weaker invasiveness (P<0.05), more dominant proliferation (P<0.001), and less apoptosis than mock cells. CONCLUSIONS: The expression of FABP6 was higher in primary colorectal cancers and adenomas than in normal epithelium, but was dramatically decreased in lymph node metastases, suggesting that FABP6 may play an important role in early carcinogenesis.     

An oral anticancer drug, TS-1, enabled a patient with advanced gastric cancer with Virchow's metastasis to receive curative resection

We encountered a patient with advanced gastric cancer, with Virchow's lymph node metastasis, who subsequently underwent curative resection after neoadjuvant chemotherapy with the newly developed oral anticancer drug, TS-1. The patient was a 67-year-old woman who had a type 2 tumor in the middle third of the stomach, and Virchow's lymph node metastasis, which was diagnosed by fine-needle aspiration cytology; she also had swollen paraaortic lymph nodes. Curative resection was considered impossible, and TS-1 (100 mg/day) was administered for 28 days in one course, mainly in the outpatient clinic. Although grade 2 stomatitis interrupted the therapy on day 21 of the second course and on day 7 of the third course, the type 2 tumor showed marked remission (partial response; PR) and the metastasis in the Virchow's and paraaortic lymph nodes had completely disappeared after the third course (complete response; CR). Eleven weeks after the completion of the TS-1 treatment, total gastric resection with D3 lymph node dissection was performed. Histopathological examination revealed tumor involvement only in the mucosal and submucosal layers of the stomach and the no. 4d lymph node. Most of the tumor was replaced with fibrosis with granulomatous change in the muscularis propria of the stomach and in the no. 3, no. 6, and no. 7 lymph nodes. This may be the first report of a patient with advanced gastric cancer with Virchow's lymph node metastasis who successfully received curative resection following neoadjuvant chemotherapy with a single oral anticancer drug. Received: August 7, 2001 / Accepted: January 28, 2002     

Effectiveness of doxifluridine (5′-DFUR)/docetaxel against advanced/recurrent gastric cancer showing resistance to various anticancer drug regimens

A 58-year-old man was diagnosed as having type 3 gastric cancer (poorly differentiated adenocarcinoma). He underwent total gastrectomy with splenectomy, as well as D3 dissection, and received postoperative chemotherapy combining oral uracil and futrafur (UFT) with cisplatin (CDDP), but results showed recurrence of multiple abdominal lymph node metastases around the aorta. He therefore received various anticancer drug regimens (irinotecan [CPT-11]/CDDP; 1 M tegafur-0.4 M gimeracil-1 M oteracil potassium [TS-1], methotrexate (MTX)/5-fluorouracil); however, final results showed growth of lymph node metastasis and simultaneous worsening of his general condition. The patient then received combined administration of doxifluridine (5′-DFUR)/docetaxel (5′-DFUR, 1000 mg/body [666.7 mg/m ² ], given by consecutive daily administration, orally, for days 1–14; and docetaxel, 80 mg/body [60 mg/m ² ], on day 8, by venous drip, every 3 weeks). Three courses of this regimen resulted in approximately 90% reduction of the abdominal lymph node size, disappearance of the right cervical lymph node metastasis, reductions of the levels of two tumor markers (carcinoembryonic antigen [CEA] and carbohydrate antigen [CA]19-9), and improvement of his general condition. In total, seven courses of the regimen were carried out. The patient died on day 298 after starting this combined regimen and showed a response period of 126 days. The primary toxicity identified was neutropenia (grade 4), as well as other low-grade (grade 1, 2) hematological and nonhematological toxicities. In the field of gastric cancer treatment, especially for patients showing multiple resistance to anticancer drugs, an effective therapy is critically needed. Received: January 15, 2002 / Accepted: July 8, 2002 Offprint requests to: A. Sato     

The FANCG Fanconi anemia protein interacts with CYP2E1: possible role in protection against oxidative DNA damage.

Fanconi anemia (FA) is a genetic disorder that leads to aplastic anemia and birth defects and predisposes to cancer. FA cells exhibit characteristic hypersensitivity to DNA cross-linking agents such as mitomycin C (MMC), and FANCG is one of six known FA gene products. By immunocytochemical analysis of transfected cells, we discovered that although FANCG localized to both the nucleus and cytoplasm, there was an increase in cells with predominantly cytoplasmic staining after treatment with MMC. Concurrently, while searching by two-hybrid analysis for proteins that associate with FANCG, we identified a novel interaction between FANCG and cytochrome P450 2E1 (CYP2E1). A member of the P450 superfamily, CYP2E1 is associated with the production of reactive oxygen intermediates and the bioactivation of carcinogens. High constitutive levels of CYP2E1 were found in a FA-G lymphoblast cell line, whereas complementation of the FA-G line with wild-type FANCG was associated with decreased CYP2E1. These findings suggested that the interaction of FANCG with CYP2E1 might alter redox metabolism and increase DNA oxidation. Using a fluorescent assay, we found a dose-dependent increase in the oxidized DNA base, 8-oxoguanine (8-oxoG), after treatment of mutant FA-G cells with H(2)O(2) or MMC. Conversely, significantly lower levels of 8-oxoG were detected in FANCG-complemented FA-G cells. We conclude that the unknown function of FANCG involves at least transient interaction with cytoplasmic components, possibly including CYP2E1, and propose a role for FANCG in protection against oxidative DNA damage.     

Therapeutic potential of a reduced-intensity preparative regimen for allogeneic transplantation with cladribine, busulfan, and antithymocyte globulin against advanced/refractory acute leukemia/lymphoma.

PURPOSE: Cladribine (2-CdA) is a purine analogue that exhibits activity against a variety of hematological malignancies and has a potent immunosuppressive effect. We therefore performed a pilot study to evaluate the feasibility of a novel 2-CdA-based reduced-intensity stem cell transplantation (RIST) regimen. EXPERIMENTAL DESIGN: A total of 16 scheduled patients with hematological malignancies were enrolled for comparison of their data with conventional stem cell transplantation (n = 19). The regimen for RIST consisted of 2-CdA (0.11 mg/kg/day for 6 days), busulfan (4 mg/kg/day for 2 days), and rabbit antithymocyte globulin (2.5 mg/kg/day for 4, 2, or 0 days). The underlying diseases included acute myelogenous leukemia (n = 6), chronic myelogenous leukemia (n = 2), myelodysplastic syndrome (n = 6), and non-Hodgkin's lymphoma (n = 2). RESULTS: After RIST, four patients died before day 100 as a result of acute graft-versus-host disease (n = 1), bacteremia (n = 1), disseminated candidasis (n = 1) and congestive heart failure (n = 1). Another patient died of cerebral infarction on day 140. Thus, acute-phase regimen-related toxicities >grade III were observed in only one patient. Engraftment and complete donor chimerism were achieved by day 28 in 14 evaluable patients, and 6 of them (43%) experienced grade II-IV acute graft-versus-host disease. With a median follow-up of 328 days (range, 231-633 days), the actuarial 1-year overall and disease-free survival rates were 69% and 50%, respectively. Notably, among seven high-risk patients (five patients had been in complete remission two or more times and two not in complete remission with refractory disease at transplant), only two patients developed leukemia relapse after RIST. Although the recovery of CD4+ cells was significantly slower (P = 0.02) in RIST than in conventional stem cell transplantation, the incidence of clinically documented infections was not significantly different between the two groups. CONCLUSION: The results suggest that this novel regimen containing 2-CdA is well tolerated and induces early complete donor chimerism. The unexpected durable remission achieved in patients with advanced disease at transplant suggests the presence of an acceptable antileukemia/lymphoma effect, which would warrant a further clinical trial.     

Cellular and biochemical mechanisms of the resistance of human cancer cells to a new anticancer ribo-nucleoside, TAS-106.

We have established variants of DLD-1 human colon carcinoma and HT-1080 human fibrosarcoma cells resistant to the new anticancer ribo-nucleosides, 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)-cytosine (ECyd, TAS-106) and 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)uracil (EUrd). Both variants were shown to have decreased (3- to 24-fold decrease) uridine-cytidine kinase (UCK) activity, and exhibited cross-resistance to EUrd and TAS-106. Based on the IC(50) values determined by chemosensitivity testing, a 41- to 1102-fold resistance to TAS-106 was observed in the resistant cells. TAS-106 concentration-dependently inhibited RNA synthesis, while its effect on DNA synthesis was negligible. The degree of resistance (14- to 3628-fold resistance) calculated from the inhibition of RNA synthesis tended to be close to the degree of chemoresistance of tested cells to TAS-106. The experiments on the intracellular metabolism of TAS-106 in the parental cells revealed a rapid phosphorylation to its nucleotides, particularly the triphosphate (ECTP), its major active metabolite. The amount of TAS-106 transported into the resistant cells was markedly reduced and the intracellular level of ECTP was decreased from 1/19 to below the limit of detection; however, the unmetabolized TAS-106 as a percentage of the total metabolite level was high as compared with the parental cells. The ratio of the intracellular level of ECTP between parental and resistant cells tended to approximate to the degree of resistance calculated from the inhibitory effect on RNA synthesis. These results indicate that the TAS-106 sensitivity of cells is correlated with the intracellular accumulation of ECTP, which may be affected by both the cellular membrane transport mechanism and UCK activity.     

Cloning of the 5' upstream region of the rat p16 gene and its role in silencing.

Hypermethylation of the 5' upstream region (5' region) of the human p16(CDKN2A) (p16) gene is known to cause silencing, which is involved in a wide range of human cancers. For the rat p16 gene, its 5' region has not been cloned, and it is uncertain whether surrogate use of exon 1 alpha is adequate for analysis of p16 silencing. In this study, we observed that methylation analysis of exon 1 alpha gave false positive results in three samples of normal rat mammary epithelia and in two of six primary mammary carcinomas. Therefore, we determined the nucleotide sequence of the 5' region of the rat p16 gene. To confirm that methylation status of the 5' region is correlated with p16 expression, the methylation status was analyzed by bisulfite sequencing and methylation-specific PCR in three samples of normal mammary glands, six samples of mammary carcinomas and four cell lines. The 5' region was demethylated in all of the three normal and six carcinoma samples that fully expressed p16. On the other hand, the 5' region was highly methylated in the 3Y1 cell line, which lacked p16 expression, but without deletion. These results showed that the methylation status of the 5' region was more closely correlated with p16 expression than that of the exon 1 alpha and analysis of the methylation status is useful in examining p16 silencing in various rat tumors.     

The intraductal carcinoma component is a significant prognostic parameter in patients with invasive ductal carcinoma of the pancreas.

We have sometimes encountered invasive ductal carcinomas (IDCs) of the pancreas containing intraductal carcinoma components in the intra- and / or extra-tumor area. The purpose of this study was to investigate whether intraductal carcinoma components would be useful for predicting the outcome of IDC patients. Forty-seven surgically treated IDCs were examined, and all histological tumor sections were stained with Elastica to accurately confirm intraductal carcinoma components. Well-known clinicopathological parameters that exhibited a significant correlation in the univariate analyses for predicting disease-free survival (DFS) and overall survival (OS) were entered into the Cox proportional hazard multivariate analysis. Since the lowest P-value predicting DFS or OS periods was observed in IDCs with more than 10% intraductal carcinoma components and those with 10% or less intraductal carcinoma components (P = 0.028 and P = 0.019), we established the cutoff value of intraductal carcinoma components at 10%. In the multivariate analyses for DFS and OS, the presence of more than 10% intraductal carcinoma components showed a marginally significant increase in the hazard rate (HR) of tumor recurrence (P = 0.067) and significantly increased the HR of mortality (P = 0.040). The present study demonstrated that IDCs with more than 10% intraductal carcinoma components were associated with a significantly better patient outcome than those with 10% or less intraductal carcinoma components.     

Comparison of image reconstruction algorithms in myocardial perfusion scintigraphy

The purpose of this study was to compare the clinical utility of two image reconstruction algorithms in myocardial perfusion SPECT (single-photon emission computed tomography): filtered back-projection (FBP) and ordered subset expectation maximization (OSEM). A rest/stress one-day protocol with 99mTc-MIBI or tetrofosmin was performed on 102 consecutive patients who underwent coronary angiography. After SPECT data acquisition, images were reconstructed with FBP and OSEM algorithms. We assessed diagnostic performance (sensitivity, specificity and accuracy) in detecting coronary artery stenosis and evaluated regional tracer uptake with a 4-point scoring system. Although there were no significant differences in diagnostic performance between FBP and OSEM reconstruction, the OSEM method yielded higher uptake in the RCA area than the FBP method by reducing the count-loss artifact due to hepatic uptake of the tracers. In addition, regional uptake in the LCX area was significantly lower in the OSEM image than in the FBP image; this phenomenon was observed mainly in patients with coronary stenosis and/or infarction in the LCX territory. In conclusion, OSEM and FBP offered comparable diagnostic performance in stress myocardial perfusion SPECT. The OSEM method contributed to reduction of the count-loss artifact in inferior and posterior walls and to easy recognition of hypoperfusion in the LCX area.