Takashi Sakatani

Expression of survivin messenger RNA correlates with poor prognosis in patients with hepatocellular carcinoma.

Suppression of apoptosis is important for carcinogenesis and tumor growth. Recent studies revealed that survivin not only inhibited apoptosis but also accelerated cancer cell proliferative activity. To investigate the prognostic role of expression of the antiapoptosis gene, survivin, in hepatocellular carcinoma (HCC), the authors analyzed the correlation between the expression pattern of survivin messenger RNA (mRNA) and clinicopathologic findings of patients. Tissues were obtained by surgical resection of livers from 51 patients with HCC and 6 patients without HCC. Expression of survivin mRNA was evaluated using reverse transcription-polymerase chain reaction in 51 tumors, 51 adjacent histologically noncancerous livers, and 6 normal livers. Survivin protein expression was evaluated using Western blotting, and apoptotic cancer cells were detected by immunostaining with polyclonal rabbit anti-single-stranded DNA. Survivin mRNA expression was detected in 21 of 51 (41%) tumors, 2 of 51 (4%) noncancerous livers, and none of the 6 normal livers. Survivin mRNA expression did not correlate with tumor size or stage of HCC. Percentage of apoptotic cancer cells of 30 survivin mRNA-negative tumors (5.2 ± 3.4%) was significantly higher than that of 21 survivin mRNA-positive tumors (2.2 ± 2.3%, P = 0.0019). The disease-free 5-year survival rate of 21 patients positive for survivin mRNA (19%) was significantly poorer than that of 30 patients negative for survivin mRNA (39%, P = 0.0148). Survivin mRNA was detected in 57% (17/30) patients with HCC recurrence but in only 19% (4/21) of patients without recurrence (P = 0.0072). These results indicated that survivin mRNA expression could be used as an independent prognostic factor for patients with HCC after hepatectomy.

In vivo transfer of hepatocyte growth factor gene accelerates proliferation of hepatic oval cells in a 2‐acetylaminofluorene/partial hepatectomy model in rats

To clarify the effect of hepatocyte growth factor (HGF) on proliferation of hepatic oval cells, we transferred HGF gene into liver of the Solt–Farber rat model. Male Fisher 344 rats were infected with a recombinant adenovirus carrying the cDNA for HGF (pAxCAHGF) from tail vein. HGF mRNA showed its peak at 4 days, and diminished thereafter. The total and proliferating cell nuclear antigen‐positive hepatic oval cells were significantly elevated in HGF‐transferred rats, in which stem cell factor and c‐kit mRNA increased at each time point. Our results suggest that in vivo transfer of the HGF gene into liver accelerates proliferation of hepatic oval cells in the Solt–Farber model in rats.

Cyclin D1 expression and retinoblastoma gene protein (pRB) expression in esophageal squamous cell carcinoma

Purpose: Alterations in the cell cycle regulatory cyclin/retinoblastoma protein (pRB) pathway play a important role in tumor progression in esophageal squamous cell carcinoma (ESCC). In the present study, we evaluated the prognostic significance of the combined analysis of cyclin D1 and pRB in ESCC retrospectively. Methods: Immunoreactivities of cyclin D1 and pRB were evaluated in 148 surgically resected ESCC by use of monoclonal antibodies. Disease-free survival of patients was compared among the four subgroups according to the phenotypes of cyclin D1 and pRB expressions. Results: High immunoreactivities of pRB and cyclin D1 were detected in 64.2% and 40.5% of tumors, respectively. The loss of pRB expression and overexpression of cyclin D1 correlated with short survival. However, these factors were not detected as independently prognostic in multivariate analysis. In 107 surviving patients who underwent curative operation, co-expressed pRB and cyclin D1 (pRB+/cyclin D1+: 29 patients) were correlated with unfavorable prognosis (disease-free 5-year survival rate: 42.7%) and high cancer recurrence rate (44.8%) compared with that of 40 patients with pRB+/cyclin D1- tumors (70.5% and 27.5%). The disease-free 5-year survival rate of patients with pRB+/cyclin D1- tumors was significantly better than that of other groups (P=0.001). However, the disease-free 5-year survival rate of 29 patients with pRB+/cyclin D1+ tumors was equivalent to that of 29 patients with pRB-/cyclin D1- tumors (48.3%), and that of nine patients with pRB-/cyclin D1+ tumors (22.2%, P=0.237). Conclusions: Our results suggest that overexpression of cyclin D1 may suppress pRB function, and that combined analysis of pRB and cyclin D1 may be a useful parameter of patient prognosis in ESCC.

Clinicopathological value of immunohistochemical detection of occult involvement in pT3N0 gastric cancer.

Background. In cases of pT3 gastric cancer, even when standard histological staining reveals no evidence of metastases in the regional lymph nodes, patients still may die of postoperative recurrence of the tumor. An attempt was made in the present study to explain the unfavorable outcome of such patients by investigating the presence of occult cancer cells in lymph nodes by immunostaining of cytokeratin. Methods. We examined 2310 lymph nodes that had been removed from 83 patients with stage II gastric cancer (pT3, N0, M0). Two consecutive sections of 4 μm thick were prepared for simultaneous staining with hematoxylin and eosin and immunostaining with the CAM 5.2 monoclonal antibody against cytokeratin, respectively. Results. Evidence of occult involvement was found in 299 of 2310 (13%) lymph nodes and in 54 of 83 (65%) patients with pT3 gastric cancer. An analysis of survival demonstrated the limited 5-year survival of patients with occult involvement in their resected lymph nodes, as compared with that of patients without involvement (P < 0.01). Moreover, the patients in whom group 2 lymph nodes had occult cancer cells had a significantly poorer prognosis than those in whom occult involvement was limited to group 1 lymph nodes (P < 0.05). Conclusions. The accuracy of predictions of prognosis of patients with pT3 gastric cancer should be greatly enhanced if cytokeratin-specific immunostaining is performed in conjunction with routine histopathological examination of lymph nodes.

Expression of heavy subunit of γ-glutamylcysteine synthetase (γ-GCSh) in human colorectal carcinoma

Gamma‐glutamylcysteine synthetase (γ‐GCS) is a heterodimer consisting of heavy (γ‐GCSh) and light (γ‐GCSl) subunits. γ‐GCS catalyzes the rate‐limiting de novo biosynthesis of glutathione (GSH), an abundant physiological antioxidant that plays important roles for regulating oxidative stress. Expression of γ‐GCSh and γ‐GCSl are sensitive to oxidative stress. To investigate whether expression of γ‐GCS is correlated with tumor progression, we used immunohistochemical approaches to examine 16 human colorectal adenomas and resected 57 carcinomas from untreated patients. In adjacent normal colorectal epithelium, levels of γ‐GCSh expression were low. Strong cytoplasmic staining for γ‐GCSh was detected in 3 (18.8%) adenoma and 48 (84.2%) carcinomas. The frequency of γ‐GCSh expression in carcinoma was significantly higher than in adenoma (p<0.0001). We used RNase protation assay and Western blot to determine levels of γ‐GCSh mRNA and protein from 10 pairs of matched carcinomas with adjacent normal controls. Elevated expression of both γ‐GCSh mRNA and protein were found in 6 cases, suggesting that transcriptional and/or posttranscriptional regulation play an important role in the upregulation of γ‐GCS during colorectal carcinogenesis. We also examined the expression of another redox‐regulated gene, multidrug resistance protein 1 (MRP1). Strong staining for MRP1 was detected in 1 (6.3%) adenoma and 40 (70.2%) carcinomas. The frequency of MRP1 expression in carcinoma was significantly higher than in adenoma ( p<0.0001). Nuclear p53 expression was detected in 30 (52.6%) of carcinomas. There is a significant correlation between γ‐GCSh and MRP1 expression (p=0.013) but not between γ‐GCSh and p53. Since γ‐GCS is a sensor of oxidative stress, these results are consistent with the notion that oxidative stress is associated with colorectal tumor progression.

Thymidine phosphorylase expression in human colorectal mucosa, adenoma and carcinoma: Role of p53 expression

The enzyme, thymidine phosphorylase (dThdPase) is identical to platelet‐derived endothelial cell growth factor (PD‐ECGF), which acts as a potent angiogenic factor. The present study immunohistochemically examined the expression of dThdPase in human colorectal mucosa, adenomas and carcinomas, as well as six cultured colorectal carcinoma cell lines, in terms of intratumoral microvessel density (IMVD) and P53 expression. Thymidine phosphorylase was observed in lymphocytes, fibroblasts and macrophages, as well as smooth muscle cells and Schwann cells in the peripheral nerve fibers. The dThdPase‐positive stromal cells apparently outnumbered the normal epithelial cells, adenoma and carcinoma cells with dThdPase. Weak but obvious cytoplasmic immunoreactivity was noted in a few normal colonic epithelia, predominantly the upper surface area, while a few adenoma cells showed weak nuclear immunostaining for dThdPase in six (24%) of the 25 colonic adenomas. Expression of dThdPase was noted in 33 (73.3%) of the 45 Dukes A and B, 14 (51.9%) of the 27 Dukes C and 14 (56.0%) of the 25 Dukes D carcinomas. The mean IMVD was 84.0 ± 26.2 in the 36 dThdPase‐negative carcinomas and 97.9 ± 31.6 in the 61 dThdPase‐positive carcinomas, the value being significantly higher in the latter group (P< 0.05). The frequency of dThdPase expression was significantly lower in the P53‐negative carcinomas than in the positive carcinomas (P< 0.05). Western blot analysis showed the highest expression of dThdPase in LoVo carrying the wild‐type p53 gene, followed by Colo201, Colo320, DLD‐11 and WiDr carrying the mutated gene. These results indicate that: (i) the main source of dThdPase is stromal cells, including lymphocytes and macrophages in both colorectal normal and carcinoma tissues; (ii) dThdPase may take part in the induction of intratumoral microvessels, regardless of tumor stage; and (iii) expression might be modulated by not only P53 but also other molecules.

Thymidine phosphorylase expression results in a decrease in apoptosis and increase in intratumoral microvessel density in human gastric carcinomas.

Abstract Thymidine phosphorylase (dThdPase) / platelet- derived endothelial cell growth factor (PD-ECGF) is expressed at higher levels in a variety of human carcinomas than in adjacent normal tissue. The higher expression is associated with an increase in intratumoral microvessel density (IMVD) and an unfavorable patient prognosis. This study examined the role of dThdPase in apoptosis, IMVD and p53 expression in human gastric carcinomas. dThdPase expression was noted in 12 (35.3%) of 34 early carcinomas, and in 20 (55.6%) of 36 advanced carcinomas. At least 10 areas consisting of carcinoma cells with diffuse dThdPase expression from the 32 dThdPase-positive tumors (category I), and 10 areas without dThdPase expression from the 38 negative tumors (category II) were selected from each case. For early gastric carcinoma, the mean IMVD was 88.8±19.4 in category I and 61.4±17.3 in category II carcinomas, while for advanced gastric carcinoma, the mean IMVD was 98.8±21.0 in category I and 76.0±27.1 in category II carcinomas. The mean IMVD was significantly higher in category I than in category II tumors (P<0.05). The mean apoptotic index (AI: percentage of apoptotic cells) was 1.95±1.30 in category I, and 3.76±1.49 in category II carcinomas for early gastric carcinoma, and 1.51±0.98 in category I and 2.14±0.66 in category II carcinomas for advanced gastric carcinoma, the value of the mean AI being significantly (P<0.05) higher in dThdPase- negative tumors (category II) than in the positive tu-mors (category I), regardless of tumor stage or histological type. There was a significant inverse correlation (P<0.001) between AI and IMVD. These results indicate that dThdPase expression is associated with both an increase in intratumoral microvessels and a decrease in apoptosis in human gastric carcinomas.

Elastofibroma of the sigmoid colon.

A case of elastofibroma occurring in the sigmoid colon of a 69 year-old woman is reported. The woman presented for survey of her gastrointestinal tract. Colonoscopy disclosed two polyps in the sigmoid colon, one of which was clinically considered to be recurrent adenoma. Histologically, the lesion had characteristic eosinophilic fibers and globules, termed elastofibroma fibers with hematoxylin and eosin stain. In addition, these elastinophilic materials were digested by elastase. Histological evaluation confirmed the diagnosis of elastofibroma. Our case might suggest that it is the result of long-term fibrosis after previous endoscopic resection of a sigmoid colonic adenoma.

Clinicopathological significance of cathepsin D expression in gastric adenocarcinoma.

Objective: An estrogen-regulated lysosomal protease, cathepsin D, has been detected in a variety of tissues. This proteinase has been described as closely associated with tumor progression and metastasis in malignant tumors. The purpose of this study was to determine the clinicopathological and prognostic significance of cathepsin D expression in gastric adenocarcinoma. Methods: In a consecutive series of 478 patients with gastric carcinoma (median follow-up period: 93 months, range: 1–285 months), cathepsin D expression in tumors was quantitatively analyzed with immunohistochemistry using a monoclonal antibody against cathepsin D (clone: 1C11). The percentage of cathepsin-D-positive cancer cells (the CD index) was calculated. In addition, the amount of cathepsin-D-positive stromal cells was evaluated; three grades (high, intermediate, and low) were used for the classification. Results: The mean CD index of 478 tumors was 12.8% (range: 0–100%, median: 8%). The mean CD index of diffuse-type gastric carcinomas (14.9%) was significantly higher than that of intestinal-type carcinomas (10.1%, p < 0.0001). Cathepsin D expression of cancer cells was significantly associated with the depth of tumor invasion in both types. The percentage of tumors with high cathepsin D expression in stromal cells was significantly higher in well-differentiated tumors (25.5%) than in moderately differentiated (12.8%) or in poorly differentiated tumors (19.1%). Cathepsin D expression of stromal cells was significantly associated with the depth of tumor invasion in the intestinal type, in contrast to the diffuse type. Highly expressed cathepsin D in cancer cells was associated with a poor prognosis in both types of carcinoma, but in stromal cells highly expressed cathepsin D was associated to a poor prognosis in the intestinal type only. Conclusion: These results indicate that cathepsin D expression in cancer cells may play an important role in tumor progression in diffuse-type gastric carcinoma, whereas in the intestinal type of carcinoma, cathepsin D expression in stromal cells may play an important role in tumor progression.

Histopathology of a human allografted kidney with clinically sufficient function

To clarify the clinico‐pathological significance of protocol biopsy and clinically silent rejection in the management of renal graft recipients, we selected a total of 139 (23%) from 604 biopsy specimens according to the following criteria: 1) less than 1.4 mg/dL of serum creatinine and 2) more than 1 500 mL/d of urine volume at time of biopsy. Clinical indications for the biopsy were classified into five categories: i) protocol biopsy (73 specimens), including 69 cases at discharge post‐transplantation; ii) slight increase in serum creatinine (32); iii) proteinuria (20); iv) evaluation of pulse‐therapy (13); and v) fever elevation (1). Except for the last category, the specimens were histopathologically diagnosed as being normal in 50 (68%), 6 (17%), 1 (5%), and 5 (38%) specimens, respectively. Even borderline changes, and mild acute rejection, as well as drug‐induced nephropathy were included, implying the existence of clinically silent rejection or drug‐induced nephropathy. Obvious diversity in the histopathological diagnosis was noted in category iii) showing proteinuria, which was mainly caused by chronic rejection, drug‐induced nephropathy and glomerulonephritis. The graft survival rate was no different among the four categories, except for category v). These results indicate that biopsies obtained from functionally sufficient renal grafts could provide useful information in the management of the recipients. The clinical significance of protocol biopsy awaits further clarification by the analysis of a large number of cases.