Different survival outcomes after curative R0-resection for Eastern Asian and European gastric cancer: Results from a propensity score matched analysis comparing a Korean and a German specialized center

Several retrospective analyses on patients who underwent gastric cancer (GC) surgery revealed different survival outcomes between Eastern (Korean, Japanese) and Western (USA, Europe) countries due to potential ethnical and biological differences. This study investigates treatment outcomes between specialized institution for GC in Korea and Germany.The prospectively documented databases of the Gastric Cancer Center of the National Cancer Center, Korea (NCCK) and the Department of Surgery of the Technische Universitaet Muenchen (TUM), Germany were screened for patients who underwent primary surgical resection for GC between 2002 and 2008. Baseline characteristics were compared using χ testing, and 2 cohorts were matched using a propensity score matching (PSM) method. Patients' survival was estimated using Kaplan-Meier method, and multivariable Cox proportional hazard model was used for comparison.Three thousand seven hundred ninety-five patients were included in the final analysis, 3542 from Korea and 253 from Germany. Baseline characteristics revealed statistically significant differences for age, tumor location, pT stage, grading, lymphatic vessel infiltration (LVI), comorbidities, number of dissected lymph nodes (LN), postoperative complications, lymph-node ratio stage, and application of adjuvant chemotherapy. After PSM, 171 patients in TUM were matched to NCCK patients, and baseline characteristics for both cohorts were well balanced. Patients in Korea had significantly longer survival than those in Germany both before and after PSM. When the analysis was performed for each UICC stage separately, same trend was found over all UICC stages before PSM. However, significant difference in survival was observed only for UICC I after PSM.This analysis demonstrates different survival outcomes after surgical treatment of GC on different continents in specialized centers after balancing of baseline characteristics by PSM.

Efficacy of argon plasma coagulation in the treatment of radiation-induced hemorrhagic gastroduodenal vascular ectasia

OBJECTIVE

Radiation-induced hemorrhagic gastroduodenal vascular ectasia (GDVE) is rare but difficult to manage. Argon plasma coagulation (APC) has not yet been evaluated in the treatment of radiation-induced hemorrhagic GDVE. The efficacy of APC in patients with radiation-induced hemorrhagic GDVE has been investigated in this article.

MATERIAL AND METHODS

Eighteen patients with upper gastrointestinal (GI) bleeding caused by radiation-induced GDVE, including 13 with hepatocellular carcinoma, 3 with pancreatic cancer, and 2 with cholangiocarcinoma, were treated with APC. The efficacy of APC was retrospectively evaluated, based on cessation of macroscopic GI bleeding, resolution or stabilization of anemia and transfusion dependence, endoscopic ablation of almost all vascular lesions, complications, and recurrence.

RESULTS

Mean patient age was 59 years (range 42-80 years). The median time from radiation to GDVE diagnosis was 4.6 months (range 3.3-21.5 months). The median number of APC sessions per patient was 2.4 (range 1-4). All 18 patients showed an endoscopic response to APC treatment, with sustained increases in mean hemoglobin level, from 6.6 g/dL (range 2.9-9.5 g/dL) to 9.7 g/dL (range 7.1-12.7 g/dL) (p < 0.001), and decreased dependence on transfusion, from 9.1 (range 0-30) to 4.1 (range 0-15) units of packed red blood cells per patient (p = 0.038) after last endoscopic eradication by APC treatment. There were no major procedure-related adverse events or deaths. At a median follow up of 4.7 months (range 0.6-24.5 months), none of the patients experienced recurrence of GDVE.

CONCLUSIONS

APC showed short-term effectiveness and safety in the treatment of radiation-induced hemorrhagic GDVE.

ALU and LINE-1 hypomethylations in multistep gastric carcinogenesis and their prognostic implications

Focal CpG island hypermethylation and diffuse genomic hypomethylation signify the changes in the DNA methylation status in cancer cells. ALU and LINE-1 repetitive DNA elements comprise ~28% of the human genome. PCR-based measurements of these repetitive DNA elements can be used as a surrogate marker of the genomewide methylation content. Our study aimed to identify the timing of ALU and LINE-1 hypomethylations during multistep gastric carcinogenesis and their prognostic implications in gastric cancer (GC). In our study, we analyzed the methylation statuses of ALU and LINE-1 in 249 cases of gastric biopsy samples and another independent set of 198 cases of advanced GC by pyrosequencing. Regardless of the Helicobacter pylori infection status, a significant decrease in the ALU methylation levels was noted during the transitions from chronic gastritis to intestinal metaplasia and from gastric adenoma to GC. LINE-1 methylation decreased during the transition from intestinal metaplasia to gastric adenoma and no further decrease occurred during the transition from gastric adenoma to GC. A low LINE-1 methylation status was strongly associated with poor prognosis in GC. A multivariate analysis revealed that LINE-1 methylation status was an independent prognostic factor. Our findings suggest that ALU and LINE-1 hypomethylations are early events during multistep gastric carcinogenesis. Furthermore, the LINE-1 methylation status can be used as a molecular biomarker to define a subset of GC patients with poor prognosis.

Comparison of surgical performance and short-term clinical outcomes between laparoscopic and robotic surgery in distal gastric cancer

AIMS

The authors aimed to compare the surgical performance and the short-term clinical outcomes of robotic assisted laparoscopic distal gastrectomy (RADG) with laparoscopy-assisted distal gastrectomy (LADG) in distal gastric cancer patients.

METHOD

From April 2009 to August 2010, 62 patients underwent LADG and 30 patients underwent RADG for preoperative stage I distal gastric cancer by one surgeon at the National Cancer Center, Korea. Surgical performance was measured using lymph node (LN) dissection time and number of retrieved LNs, which were viewed as surrogates of technical ease and oncologic quality.

RESULTS

In clinicopathologic characteristics, mean age, depth of invasion and stage were significantly different between the LADG and RADG group. Mean dissection time at each LN station was greater in the RADG group, but no significant intergroup difference was found for numbers of retrieved LNs. Furthermore, proximal resection margins were smaller, and hospital costs were higher in the RADG group. In terms of the RADG learning curve, mean LN dissection time was smaller in the late RADG group (n = 15) than in the early RADG group (n = 15) for 4sb/4d, 5, 7-12a stations, but numbers of retrieved LNs per station were similar.

CONCLUSION

With the exception of operating time and cost, the numbers of retrieved LNs and the short-term clinical outcomes of RADG were found to be comparable to those of LADG, despite the surgeon's familiarity with LADG and lack of RADG experience. Further studies are needed to evaluate objectively ergonomic comfort and to quantify the patient benefits conferred by robotic surgery.

Is the sentinel node biopsy clinically applicable for limited lymphadenectomy and modified gastric resection in gastric cancer? A meta-analysis of feasibility studies

BACKGROUND

Sentinel node biopsies (SNBs) have been clinically applied in melanoma and breast cancer for limited lymphadenectomy. However, the use of SNB remains controversial in gastric cancer due to unsatisfactory sensitivity and variability. This meta-analysis was performed to determine the sensitivity of SNB in gastric cancer and to identify factors that improve its sensitivity.

METHODS

Feasibility studies on SNB in gastric cancer were searched for from 2001 to 2009 in Pubmed, Cochrane, and Embase. Forty-six reports, which included 2,684 patients, were found. Estimated sensitivities, detection rates, and negative (NPV), and positive predictive values (PPV) were calculated using a random effects model. Inter-study heterogeneity, meta-regression, and subgroup analysis for sensitivity was performed.

RESULTS

The estimated sensitivity, detection rate, NPV, and PPV were 87.8%, 97.5%, 91.8%, and 38.0%, respectively, with significant inter-study heterogeneity (P < 0.0001). However, no significant contributor to heterogeneity was identified. By subgroup analysis, sensitivity was found to depend significantly on the number of SNs harvested.

CONCLUSIONS

SNB in gastric cancer is probably not clinically applicable for limited lymphadenectomy due its unsatisfactory sensitivity and heterogeneity between practicing surgeons. To improve sensitivity, more than four SNs should be harvested, and a tumor specific SNB method should be developed.

Oncologic effectiveness of regular follow-up to detect recurrence after curative resection of gastric cancer

BACKGROUND

While clinicians routinely follow up gastric cancer patients after curative resection to detect recurrence, the effectiveness of regular follow-up has not been proven, and no consensus has been reached regarding follow-up programs.

METHODS

Of the 1,767 patients who underwent curative resection for gastric cancer from 2001 to 2004, 310 (17.5%) developed recurrence during follow-up. The oncologic effectiveness of follow-up was evaluated using recurrence detection rates during follow-up and survivals. Clinicopathologic characteristics, the detection tools used, and times lapsed between recurrence and previous examinations were also investigated.

RESULTS

Two hundred thirty-three (75.2%) of the 310 patients who developed recurrence were detected by regular follow-up (detected group). The frequencies of undifferentiated and diffuse-type recurrences were higher in patients with recurrence detected based on patient-initiated findings (undetected group) than in the detected group. Computed tomography and tumor markers were the first detection tools that yielded positive findings. Times between recurrence detection and previous examinations ranged from 2.8 to 5.3 months over the first 2 years. No difference in overall survival was found between the detected and undetected groups (log rank, P = 0.2).

CONCLUSIONS

The oncologic effectiveness of regular follow-up after curative resection for gastric cancer was found to be unsatisfactory. A large-scale randomized controlled trial is required to identify the effectiveness of regular follow-up in terms of its oncologic, functional, psychological, and economical aspects.

CpG island hypermethylator phenotype in gastric carcinoma and its clinicopathological features

Gastric carcinoma (GC) is one of the human cancers in which promoter CpG island hypermethylation is frequently found. CpG island methylator phenotype (CIMP) refers to a subset of GCs which harbor concordant methylation of multiple promoter CpG island loci. However, little is known regarding clinicopathological features of CIMP-positive (CIMP-high) GC. Our study aimed to characterize clinicopathological features of CIMP-high GC. We analyzed 196 cases of GCs for their methylation status in 16 cancer-specific CpG island loci using MethyLight assay and arbitrarily defined CIMP-high GC as those with methylation at 13 or more CpG island loci. With exclusion of microsatellite instability-positive GC and EBV-positive GC from the analysis, CIMP-high GC (n = 10, 6.7%) demonstrated tendency toward higher cancer stage, infiltrative growth type, poor differentiation, and diffuse or mixed type of Lauren classification. CIMP-high GC showed significantly shortened survival compared with that of CIMP-negative GC. When CIMP-negative GC (methylation at 12 or less) was divided into CIMP-intermediate and CIMP-low (methylation at one or none), CIMP-low exhibited better clinical outcome than CIMP-intermediate. Hypermethylation at 14 CpG island loci or more was closely associated with poor clinical outcome and found to be an independent prognostic factor. Our findings that CIMP-high GCs were featured with characteristic clinicopathological parameters, including poor prognosis are distinct from previous studies. More extensive, large-scaled study is necessary to validate the findings of the present study.

CpG island hypermethylator phenotype in gastric carcinoma and its clinicopathological features

Gastric carcinoma (GC) is one of the human cancers in which promoter CpG island hypermethylation is frequently found. CpG island methylator phenotype (CIMP) refers to a subset of GCs which harbor concordant methylation of multiple promoter CpG island loci. However, little is known regarding clinicopathological features of CIMP-positive (CIMP-high) GC. Our study aimed to characterize clinicopathological features of CIMP-high GC. We analyzed 196 cases of GCs for their methylation status in 16 cancer-specific CpG island loci using MethyLight assay and arbitrarily defined CIMP-high GC as those with methylation at 13 or more CpG island loci. With exclusion of microsatellite instability-positive GC and EBV-positive GC from the analysis, CIMP-high GC (n = 10, 6.7%) demonstrated tendency toward higher cancer stage, infiltrative growth type, poor differentiation, and diffuse or mixed type of Lauren classification. CIMP-high GC showed significantly shortened survival compared with that of CIMP-negative GC. When CIMP-negative GC (methylation at 12 or less) was divided into CIMP-intermediate and CIMP-low (methylation at one or none), CIMP-low exhibited better clinical outcome than CIMP-intermediate. Hypermethylation at 14 CpG island loci or more was closely associated with poor clinical outcome and found to be an independent prognostic factor. Our findings that CIMP-high GCs were featured with characteristic clinicopathological parameters, including poor prognosis are distinct from previous studies. More extensive, large-scaled study is necessary to validate the findings of the present study.

Risk factors for lymph node metastasis in patients with early gastric cancer and signet ring cell histology

BACKGROUND

Early gastric cancer with signet ring cell histology has been reported as a favourable histological type. The aim of this study was to identify risk factors associated with lymph node metastasis in patients with this type of early gastric cancer.

METHODS

A cross-sectional study of patients with early gastric cancer with differentiated and signet ring cell histology undergoing surgery was conducted. Risk factors were evaluated using multiple logistic regression analysis with odds ratios and 95 per cent confidence intervals.

RESULTS

In 1362 patients undergoing gastrectomy for early gastric cancer, the rate of lymph node metastasis was similar for tumours with signet ring cell and differentiated histological findings (10.7 versus 9.0 per cent respectively; P = 0.307). Logistic regression analysis showed that depth of tumour invasion was predictive of lymph node metastasis in patients with signet ring cell histology (P < 0.001). Tumour size was not associated with lymph node metastasis in either univariable or multivariable analysis. Lesions smaller than 2 cm were not uncommon in patients with signet ring cell gastric tumours and lymph node metastases (six of 48; 13 per cent).

CONCLUSION

Patients with early gastric cancer with signet ring cell-type histology are probably best treated by gastrectomy with lymph node dissection.

Mixed-type gastric cancer and its association with high-frequency CpG island hypermethylation

Gastric carcinoma (GC) is one of the human cancers in which promoter CpG island hypermethylation is frequently found. We used the MethyLight assay to evaluate the methylation status of 16 CpG island loci that are hypermethylated in GC. We analyzed the relationship between CpG island hypermethylation of these 16 genes and the clinicopathological features in 191 advanced GCs. A significant difference was observed between the number of methylated genes in Epstein-Barr virus (EBV)-negative and microsatellite instability (MSI)-negative GCs of different histological types (Lauren classification; P < 0.01). We found that mixed-type (MT) carcinomas, which have both diffuse-type (DT) and intestinal-type (IT) components, had more methylated genes (10.6) than either DT carcinomas (7.6 methylated genes) or IT carcinomas (6.7 methylated genes) (P < 0.001). This trend was also observed when EBV-positive or MSI-positive GCs were excluded from the analysis (9.2, 6.9, and 4.8; P < 0.001). When the IT and DT components were dissected from MT carcinomas and the methylation of these 16 genes was evaluated, both components had a number of methylated genes similar to MT carcinomas, (10.2 and 9.7, respectively), which was significantly higher than was found in IT and DT carcinomas (P < 0.05). These findings indicate that MT carcinoma is distinct from IT and DT carcinomas in its enhanced CpG island hypermethylation status and implicate the enhanced promoter CpG island hypermethylation in the histogenesis of MT carcinoma.

Preoperative serum angiopoietin-2 levels correlate with lymph node status in patients with early gastric cancer

BACKGROUND

Lymph node metastasis is the most important factor to consider when deciding on the modality of resection in patients with early gastric cancer. The aim of the present study was to assess the relationship between preoperative serum angiopoietin-2, a lymphangiogenic growth factor, and lymph node metastasis in patients with early gastric cancer.

METHODS

A total of 62 preoperative serum samples from patients diagnosed with early gastric adenocarcinoma, and 30 serum samples from healthy donors were obtained. The serum levels of angiopoietin-2 (Ang-2) were quantified by immunoassay. Intra- and peritumor lymphatic vessel density (I-LVD and P-LVD) were counted after immunohistochemical staining. The relationship between the serum Ang-2 levels and other prognostic variables (tumor size, histological type, depth of tumor invasion, I-LDV, P-LDV, presence of lymph node involvement, and distant metastasis) were then examined by univariate and multivariate linear regression analyses.

RESULTS

The median serum levels of Ang-2 in patients were higher than those of healthy controls [311.1 ng/mL, interquartile range (IQR) 256.7-311.1 ng/mL versus 286.5 ng/mL, IQR 226.9-286.5 ng/mL; Mann-Whitney test, P = 0.016]. Eight patients had metastatic lymph nodes; the Ang-2 levels from the patients with metastatic lymph nodes were higher than from those with negative lymph nodes (297.5 ng/mL, IQR 251.1-385.8 ng/mL versus 416.0 ng/mL, IQR 337.1-485.5 ng/mL; Mann-Whitney test, P = 0.019). Elevated serum Ang-2 levels were associated with positive lymph node involvement and this finding was significant on univariate (P = 0.008) and multivariate logistic regression analysis (P = 0.011).

CONCLUSION

Serum Ang-2 levels were clinically useful markers for lymph node metastasis in patients with early gastric cancer.

Learning curve for identification of sentinel lymph node based on a cumulative sum analysis in gastric cancer

BACKGROUND/AIMS

Lymph node metastasis is the most important point to consider when deciding on the modality of resection in patients with early gastric cancer. This study was conducted to evaluate the learning curve for identification of sentinel lymph nodes in patients with gastric cancer.

METHODS

The investigators included the results from 2 prospective series of sentinel lymph node mapping. Cumulative sum (CUSUM) analysis was performed to assess the learning curves for identification of sentinel lymph nodes at CUSUM target success rates of 95%.

RESULTS

One surgeon performed 135 sentinel lymph node mappings for 2 prospective series. The success rate exceeded 90%. The learning period for gastric cancer sentinel node mapping was calculated to be 26 cases for achieving a 95% success rate. Multiple logistic regression analysis for successful detection of sentinel nodes showed that surgical experience of sentinel lymph node mapping was an independent factor for successful detection of sentinel nodes.

CONCLUSIONS

This study suggests that the learning period for identification of sentinel lymph nodes in gastric cancer would be 26 cases. In clinical trials for gastric cancer with sentinel lymph node mapping, the learning curve should be considered to minimize bias due to surgical factors.

Abdominal shape of gastric cancer patients influences short-term surgical outcomes

BACKGROUND

There is a prevailing belief that both obesity and abdominal shape influence abdominal accessibility, and thus affect short-term surgical outcomes of gastric cancer surgery.

METHODS

We measured the thickness of subcutaneous fat (SCF), abdominal anterior-posterior diameter (APD), transverse diameter (TD), and intra-abdominal fat volume (IFV) at the umbilicus level by using the abdominal CT scans of 291 gastric cancer patients who had undergone subtotal gastrectomy and D2 lymph node dissection. Clinicopathological factors including body mass index (BMI), APD, TD, IFV, and SCF and surgical outcomes, i.e., dissected lymph node number, morbidity, and mortality were analyzed.

RESULTS

SCF thickness, APD, TD, IFV, and BMI mean values were 20.0 mm (range 2.0-64.0), 188.4 mm (range 128.0-332.0), 301.4 mm (range 160.0-651.0), 198.3 mm(2) (range 123.4-312.1), and 23.9 kg/m(2) (range 16.6-34.6), respectively. In male patients, APD was found to correlate with the number of retrieved lymph nodes (P = 0.045). Whereas in female patients, this was not the case (P = 0.093). Twenty-one patients experienced postoperative complications but no postoperative mortality occurred. Female patients who experienced postoperative complications had higher APD (32.9 +/- 10.0 mm versus 26.1 +/- 7.9 mm, P = 0.044) and BMI (27.3 +/- 4.1 kg/m(2) versus 24.3 +/- 3.5 kg/m(2), P = 0.049) values than those who did not.

CONCLUSIONS

We conclude that obesity and abdominal shape of gastric cancer patients both influence the short-term surgical outcomes of subtotal gastrectomy with D2 lymph node dissection.

An immunohistochemical study of the expression of cell-cycle-regulated proteins p53, cyclin D1, RB, p27, Ki67 and MSH2 in gallbladder carcinoma and its precursor lesions

Gallbladder carcinomas are rare but highly lethal neoplasms. We examined the expression of five cell-cycle-related molecules (p53, RB, cyclin D1, p27, Ki-67), and MSH2, in 46 carcinomas, 14 adenomas, 15 low-grade dysplasias, 9 intestinal metaplasias and 20 normal gallbladder epithelia. The expression of these molecules was altered in gallbladder carcinomas and adenomas. In gallbladder carcinomas we observed increased expression of p53, cyclin D1, Ki-67, and MSH2 together with decreased expression of RB and p27 protein. Aberrant expression of cyclin D1 and reduced expression of RB were noted in adenomas, and expression of cyclin D1 was elevated in low-grade dysplasias. However, there was no change in the levels of these cell-cycle molecules in metaplasia. Expression of p53, p27, Ki-67, and MSH2 was correlated with clinical stage (P<0.05) and there was also a correlation between the expression of Ki-67 and MSH-2 and patient age (P<0.05). These results suggest that altered expression of cell-cycle molecules p53, cyclin D1, RB, p27, and of MSH-2 is involved in the progression of gallbladder carcinomas.

An immunohistochemical study of the expression of adhesion molecules in gallbladder lesions

We investigated the expression of 10 adhesion molecules (alpha-catenin, beta-catenin, gamma-catenin, CD44, CD44v6, ICAM-1, CD56, CEA, E-cadherin, and CD99) in 46 gallbladder carcinomas, 14 adenomas, 15 low-grade dysplasias, nine intestinal metaplasias, and 20 samples of normal gallbladder epithelium by immunohistochemistry. The expression of adhesion molecules was altered in gallbladder carcinomas and adenomas. In gallbladder carcinomas, increased expression of ICAM-1, CEA, and CD44v6 was observed, together with decreased expression of alpha/beta/gamma-catenin and CD99. In adenomas, aberrant expression of CD44v6 and CD56, as well as reduced expression of alpha/beta/gamma- and E-cadherins, was noted. Expression of alpha/beta/gamma-catenin was reduced in low-grade dysplasia, whereas there was no change in the expression of these adhesion molecules in metaplasia. Expression of ICAM-1, CD99, E-cadherin, and CD56 was correlated with clinical stage. In addition a correlation was noted between expression of ICAM-1 and E-cadherin and lymph node metastasis (p<0.05). These results suggest that altered expression of these adhesion molecules is involved in the progression and metastasis of gallbladder carcinomas.

LFA-1- and ICAM-1-dependent homotypic aggregation of human thymocytes induced by JL1 engagement

Cell-cell adhesion is essential for the appropriate immune response, differentiation, and migration of lymphocytes. This important physiological event is reflected in vitro by homotypic cell aggregation. We have previously reported that a 120 kDa cell surface glycoprotein, JL1, is a unique protein specifically expressed by immature double positive (DP) human thymocytes which are in the process of positive and negative selections through the interaction between thymocyte and antigen-presenting cells (APCs). The function of the JL1 molecule, however, is yet to be identified. We show here that anti-JL1 monoclonal antibody (mAb) induced the homotypic aggregation of human thymocytes in a temperature- and Mg2+-dependent manner. It required an intact cytoskeleton and the interaction between leucocyte function associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) since it was blocked by cytochalasin B and D, and mAb against LFA-1 and ICAM-1 which are known to be involved in the aggregation of thymocytes. Translocation of phosphatidylserine (PtdSer) through the cell membrane was not detected, implying that the molecular mechanism of JL-1-induced homotypic aggregation is different from that of CD99-induced homotypic aggregation. In summary, JL1 is a cell surface molecule that induces homotypic adhesion mediated by the LFA-1 and ICAM-1 interaction and cytoskeletal reorganization. These findings suggest that JL1 may be an important regulator of thymocyte development and thymocyte-APC interaction.

Development of new adherent mutant from human myeloma-derived cell line: in vitro model of anaplastic transformation of myeloma

Anaplastic myeloma is a rare but distinct, biologically aggressive variant of myeloma which usually results from dedifferentiation or anaplastic transformation of the myeloma cells. The molecular mechanisms that determine the biologic behavior of anaplastic myeloma and effective treatment modalities have not been well known due to lack of in vitro models. In the present study, we have developed an anaplastically transformed mutant from a human myeloma-derived cell line. In the process of long-term culture of the myeloma-derived IM-9 cell line in low serum and nutrient conditions, an adherent mutant line was developed and named IM-9/AD. This mutant cell line displayed several characteristics resembling anaplastic myeloma such as: 1, large cells with large vesicular nucleus and prominent nucleolus, multinuclearity and high mitotic figures; 2, loss of leukocyte-associated antigens; and 3, higher tumorigenecity in scid mice than its parental cell line. This newly developed mutant cell line may serve as a readily available in vitro model to investigate the biology of anaplastic myeloma.

Reduced expression of CD99 and functional disturbance in anencephalic cortical thymocytes

In a significant proportion of cases, anencephaly is associated with thymic enlargement, suggesting a possibility that anencephalic fetuses have a functional disturbance in thymocyte differentiation and development. In this report, we demonstrated that CD99 expression was consistently reduced in cortical thymocytes of all anencephalic fetuses. In addition, the CD99-dependent aggregation of immature cortical thymocytes was almost completely impaired and apoptosis of thymocytes was markedly reduced in several cases. These results are in agreement with previous findings that CD99 regulates the aggregation and apoptosis of various types of cells. These data strongly suggest that functional disturbance of thymocytes and thymic hyperplasia are related to the reduced expression of CD99 molecule in anencephalic fetuses.

ILK (beta1-integrin-linked protein kinase): a novel immunohistochemical marker for Ewing's sarcoma and primitive neuroectodermal tumour

ILK (beta1-integrin-linked protein kinase) is a recently identified 59-kDa serine/threonine protein kinase that interacts with the cytoplasmic domain of the beta1-integrin containing four ankyrin-like repeats. We have developed a polyclonal antibody against ILK and explored the ILK immunoreactivity in normal human cells and tissues. ILK was mainly expressed in cardiac muscle and skeletal muscles. Surprisingly, ILK expression was observed in Ewing's sarcoma (ES; 100%), primitive neuroectodermal tumour (PNET; 100%), medulloblastoma (100%), and neuroblastoma (33.3%), whereas other small round cell sarcomas were not stained by the anti-ILK antibody. These results suggest that ILK could be a novel marker for tumours with primitive neural differentiation. Our findings support the notion that ES is a tumour that is closely related to PNET and that both originate from the neuroectoderm. ILK may be a sensitive and specific immunohistochemical marker and useful for the positive identification of ES and PNET in formalin-fixed, paraffin-embedded tissue sections.

Effects of synthetic inhibitor of metalloproteinase and cyclosporin A on corneal haze after excimer laser photorefractive keratectomy in rabbits

To evaluate the effects of synthetic inhibitor of metalloproteinase (SIMP) and cyclosporin A (CsA) on corneal haze after excimer laser photorefractive keratectomy (PRK) in rabbits, PRK was performed on 60 rabbits. They were randomized to one of four groups: group A which received topical SIMP, group B which received topical CsA, group C which received both SIMP and CsA, and group D which received vehicles. Another 16 rabbits did not undergo PRK and were randomized to one of four groups: group E which received topical SIMP, group F which received topical CsA, group G which received both SIMP and CsA, and group H which received vehicles. SIMP solution (1 mm) was instilled every two hours and 2% cyclosporin was instilled four times a day, this was carried out for as long as 6 weeks after surgery. At one, two, four, and six weeks after surgery, slit lamp examination was performed with haze gradings recorded, and corneal specimens were obtained from groups A, B, C, and D. In groups E-H, all rabbits were killed after six weeks of eyedrops instillation. Light microscopy and immunohistochemistry for collagen types III, IV, and VI were performed on the specimens obtained. Slit lamp examination and light microscopy revealed that SIMP significantly reduced corneal haze after PRK, but CsA did not. Immunohistochemistry revealed that deposition of types III and IV collagen was detected in ablated area in groups A-D, and SIMP reduced the frequency of positive staining for type III collagen. In groups E-F, corneas were normal. These findings suggest that SIMP significantly reduced corneal haze and the synthesis of type III collagen after excimer laser PRK in rabbits.

Intracranial tuberculoma: comparison of MR with pathologic findings

PURPOSE

To compare the MR signal intensity patterns and enhancement pattern of intracranial tuberculomas with their histopathologic features.

METHODS

MR images of six patients with surgically proved intracranial tuberculoma were reviewed retrospectively and were compared with histologic findings of the resected specimen. Detailed histologic examination was performed to look for the extent and characteristics of caseation necrosis, fibrosis, and inflammatory cellular infiltrates at each area of different signal intensities and at the enhancing areas on MR. Signal intensities for T1- and T2-weighted images were compared with normal gray matter.

RESULTS

On T1-weighted images, the granulomas showed a slightly hyperintense rim surrounded by a complete or partial rim of slight hypointensity and central isointensity or mixed isointensity and hyperintensity in five patients and homogeneous isointensity in one patient. Histologically, the zone of central isointensity or mixed intensity corresponded to caseation necrosis plus adjacent cellular infiltrates. The hyperintense and hypointense rims corresponded to the layers of collagenous fiber and the layers of the inflammatory cellular infiltrates, respectively. On T2-weighted images, the entire portion of the granuloma showed slightly heterogeneous isointensity or hypointensity with small markedly hypointense foci in five patients, and a hyperintense center surrounded by a hypointense rim in one patient. Histologic layers were not discriminated on T2-weighted images. On postcontrast T1-weighted images, there were single or multiple conglomerate ring enhancements within a tuberculoma in all six patients, corresponding to the layers of both collagenous and inflammatory cells.

CONCLUSION

Combination of the described signal intensity patterns and conglomerate ringlike enhancing appearance of the lesion is characteristic of tuberculoma, and may play an important role in differentiating intracranial tuberculomas from other ring-enhancing brain lesions.