Section 1B: Rh flow cytometry. Coordinator's report. Rhesus index and antigen density: an analysis of the reproducibility of flow cytometric determination.

Fifty-seven IgG monoclonal anti-D antibodies were evaluated in the Rh flow cytometry section, in which 12 laboratories participated. Staining protocols and a fluorescein (FITC)-conjugated Fab fragment goat anti-human IgG (H + L) as a secondary antibody were recommended but not mandatory. A CcDEe red blood cell (RBC) sample that was shown to be homozygous for RHD by molecular methods was supplied and used as internal 'standard RBC' throughout all experiments. An RBC panel comprising two partial D and four weak D types was supplied as well. The use of standard RBC reduced the variability of the data among the laboratories and allowed the conversion of fluorescence data into epitope densities, which were compounded in an antigen density (antigen D per RBC). The highest antigen density was determined for DVI type III, followed by DVII and weak D type 3; the lowest antigen density were determined for weak D type 1 and type 2. Nine of the 12 participating laboratories discriminated three groups of aberrant RhD that had similar Rhesus indices (RI): D category VI with RI = 0; weak D type 2 and type 3 with an high RI; and D category VII and weak D type 1 with an intermediate RI. The antigen densities and the Rhesus indices obtained correlated well among the laboratories of this Workshop section despite different staining protocols, secondary antibodies and instrumentation.     

E-cadherin gene variants in gastric cancer families whose probands are diagnosed with diffuse gastric cancer

To identify germline E-cadherin mutations responsible for the predisposition to diffuse gastric cancer (DGC) among the Japanese, we screened 17 patients with familial aggregation of gastric cancer by sequencing analysis. All the patients were diagnosed with DGC and had at least 1 sibling with gastric cancer. Two novel E-cadherin gene variants were detected. One was detected in 1 patient only and associated with an amino acid substitution (Val/Met) at codon 832 in the region essential for binding to beta-catenin. The M832 variant was detected not only in the proband but also in 2 other gastric cancer patients in the family. Immunohistochemical analysis of gastric cancer tissue from the proband revealed that E-cadherin expression was markedly reduced and beta-catenin expression was also reduced in cancer cells. However, no significant difference in the activity of beta-catenin binding was detected between the M832 variant and V832 wild-type E-cadherin in immunofluorescence and immunoprecipitation/Western blot analyses. The other was detected in 5 patients and was located in the splice donor site (IVS1+6T/C); however, RT-PCR analysis indicated that the IVS+6C variant did not cause an aberrant splicing. Thus, the M832 variant could be a germline mutation causative of familial aggregation of DGC, although further functional studies are needed to understand the pathogenic significance of this variant.     

Radiofrequency ablation (RFA) in colorectal cancer with hepatic metastases

We considered the appropriateness of RFA, which was performed in three cases of colorectal cancer with hepatic metastases accompanied by liver cirrhosis. Case 1 involved a patient with sigmoid colon cancer ss, n1 (+) with severe hepatic dysfunction and synchronous hepatic metastases (S5, S6, S8) in which RFA was performed. After 1 year and 6 months, recurrence (S3, S4) was detected in the residual liver, and the patient is currently undergoing the IFL (CPT-11/5-FU/Leucovorin) treatment. In case 2, following a partial hepatic resection, RFA was performed for cecal cancer ss, n2(+) with synchronous hepatic metastases (S5, S6, S8). After 11 months, recurrence (S5, S6, S7) occurred in residual liver and again RFA was performed following a partial hepatic resection. Lung metastases have occurred and currently IFL (CPT-11/5-FU/Leucovorin) and WHF treatments are underway. In case 3, 4 years and 8 months after cancer of the descending colon ss, n1 (+), RFA was performed on asynchronous hepatic metastases (S5, S7, S8). The patient died of peritonitis carcinomatosa one year after RFA. In all three cases, metastases were identified by dynamic CT as low density masses with no blood flow. Necrosis in all three metastases and local control had been achieved. There were no severe complications. Under the current conditions, local coagulation methods including RFA are appropriate in those cases in which resection are not possible such as multiple metastases with severe hepatic dysfunction, etc.