Detection of HER-2/neu (c-erb B-2) DNA amplification in primary breast carcinoma. Interobserver reproducibility and correlation with immunohistochemical HER-2 overexpression.

BACKGROUND: Fluorescent in situ hybridization (FISH) has been shown to be one of the most reliable methods with which to estimate the status of the HER-2/neu (or c-erb B-2) oncogene at the DNA level. METHODS: To study interobserver reproducibility and to determine more clinically correlated criteria for HER-2/neu alterations, two observers independently estimated HER-2/neu DNA status. The correlation between the consensus HER-2/neu DNA status by FISH and HER-2/neu protein status detected by immunohistochemistry (IHC) using a polyclonal antibody was studied in 216 surgically resected breast carcinomas and 34 noncancerous tissues. RESULTS: According to the HER-2/CEP17 ratio and mean HER-2 copies per nucleus, agreement level of HER-2/neu amplification was shown to be nearly perfect between two observers (kappa statistic (kappa) = 0.94 and kappa = 0.84). Finally, 40 tumors (19%) were judged to have HER-2/neu DNA amplification, with 6 having low-level amplification (> or = 2 but < 3 folds) and 34 having high-level amplification (> or = 3 folds). One hundred seventy-six other tumors, including 3 tumors that only 1 of the observers determined to be low-level amplifiers, and 34 noncancerous tissues had no detected amplification. The DNA amplification status was concordant between invasive and intraductal components in 14 carcinomas. HER-2/neu protein overexpression of moderate (2+) or high (3+) intensity based on IHC was detected in 51 carcinomas (24%), and was 2+ in 20 carcinomas and 3+ in 31 carcinomas. The HER-2/CEP17 ratio of > or = 2 was concordant with IHC findings of 2+/3+ in 91% of carcinomas (195 of 215 carcinomas), with a sensitivity of 70% (35 of 50 carcinomas) and a specificity of 97% (160 of 165 carcinomas). High-level amplification was detected in 29 of 31 IHC 3+ cases (94%), but in only 5 of 20 IHC 2+ cases (25%) and 0 in 165 IHC 0/1+ cases. All 34 cases with high-level amplification showed an IHC score of 3+ (29 cases) or an IHC score of 2+ (5 cases), but only 1 case was found to have an IHC score of 3+ and the remainder were IHC 0/1+ in 6 low-amplification cases. The concordance rate of the high-level amplification with an IHC score of 3+ was 97% (208 of 215 cases), with a sensitivity of 94% (29 of 31 cases) and a specificity of 97% (179 of 184 cases). CONCLUSIONS: The results of the current study indicated that high-level HER-2/neu amplification and an IHC score of 3+ nearly optimally identified breast carcinomas with clinically and biologically significant HER-2/neu activation. Conversely, it was confirmed that careful interpretation of test results is required in the case of low-level amplification and/or an IHC score of 2+.

The polymorphic 43Thr bcl-2 protein confers relative resistance to autoimmunity: an analytical evaluation.

We have found a novel polymorphic (Ala43Thr; ACC-->GCC) bcl-2 allele in a Japanese population. An in vitro expression study with a mouse IL-7-dependent pre-B cell line has revealed that inhibition of the programmed cell death function of 43Thr bcl-2 protein is suppressed compared with that of normal 43Ala bcl-2 protein. Since bcl-2 expression in B-lymphoid cells elicits autoimmune disease in mice, we have investigated the possibility of whether a bcl-2 polymorphism has a different susceptibility to autoimmune disease. To evaluate the clinical impact of this polymorphism, the frequency of bcl-2 polymorphism was investigated in 221 children with insulin-dependent diabetes mellitus (IDDM), 237 adults with autoimmune disease (105 with rheumatoid arthritis, 57 with systemic lupus erythematosus, 55 with Sjögren's syndrome, and 20 others), and 290 healthy Japanese children and adults. The frequency of the 43Thr bcl-2 allele, either homozygous or heterozygous, was 14.5% in normal controls, 6.8% (P<0.01) in children with IDDM, and 8.0% (P<0.025) in adults with autoimmune disease. These results suggest that the 43Thr allele of bcl-2 confers resistance to autoimmune disease. The different anti-apoptotic function resulting from the different expression of bcl-2 protein in lymphocytes seems to be associated with the development of autoimmune disease, indicating that the bcl-2 gene affects human autoimmune disease.

Recombinant adeno-associated virus-mediated gene transfer into human leukemia cell lines.

Adeno-associated virus (AAV)-based vector is a promising gene transfer vehicle by virtue of the characteristics of wild-type AAV:tropism to a wide range of human tissues and locus-specific integration at chromosome 19q13.3. To elucidate the nature of the recombinant AAV (rAAV), transduction of neomycin phosphotransferase enzyme gene (NeoR gene) into seven human leukemia cell lines was performed. Transduction efficiencies were assessed by colony formation assay and limiting dilution assay. The results suggested that both assays are comparable. Transduction efficiencies of the NeoR gene into K-562, MEG-O1, Raji, MOLT-3, HL-60, U937 and NKM-1 at a multiplicity of infection (MOI) of 0.1 were 0.27, 0.25, 0.015, 0.009, < 0.0025 and < 0.0025%, respectively. After purification and concentration of rAAV, 27% efficiency was observed in K562 at an MOI of 7 and a linear relationship between MOI and efficiency was confirmed, suggesting that this system may be useful for gene transduction into leukemia cells. Integration of the NeoR gene into the host genome was detected by Southern blotting analysis, which showed various sizes of digested fragments. A fluorescent in situ hybridization (FISH) study was carried out on 11 clones, in all of which the NeoR gene was integrated out of chromosome 19q13.3. In five of the clones, whole chromosome painting probes revealed that the integration sites were chromosomes 1q, 2q, 2q, 11p, 12p and 13q.

Mutations of the CD40 ligand gene in 13 Japanese patients with X-linked hyper-IgM syndrome.

X-linked hyper-IgM syndrome (XHIM) is a rare primary immunodeficiency caused by a defective CD40 ligand. We identified mutations of the CD40 ligand gene in 13 unrelated Japanese XHIM patients. Of the four patients with missense mutations, one had a mutation within the transmembrane domain, and the three others had mutations affecting the TNF homology region of the extracellular domain. Two of the missense mutations resulted in the substitution of amino acids that are highly conserved in TNF family proteins. Three patients had nonsense mutations, all of which resulted in the truncation of the TNF homology domain of the CD40 ligand. Three patients had genomic DNA deletions of 2, 3 or 4 nucleotides, respectively. All of the deletions were flanked by direct repeat sequences, suggesting that these deletions were caused by slipped mispairing. Three patients had mutations within introns resulting in altered splicing, and multiple splicing products were found in one patient. Thus, each of the 13 Japanese patients had different mutations, 9 of them being novel mutations. These results indicate that mutations in XHIM are highly heterogeneous, although codon 140 seems to be a hot spot of the CD40 ligand gene since two additional point mutations were located at Trp 140, bringing the total numbers of mutations affecting codon 140 to six. In one XHIM family with a missense mutation, prenatal diagnosis was performed by single-strand conformation polymorphism analysis of genomic DNA of a male fetus.

[Neutropenia in patient with X-linked hyper-IgM syndrome].

The X-linked form of hyper-IgM syndrome (HIGM1) is a rare disorder characterized by the inability of B cells to undergo isotype switch by a deficiency of CD40 ligand (CD40L) on activated T lymphocytes. The patients suffer from recurrent infections not only due to a lack of B lymphocyte activation but also due to defect of T lymphocyte functions. In addition, neutropenia is frequently accompanied by these symptoms. A patient with HIGM1, we experienced, suffered from recurrent infections and neutropenia. But he had a normal number of hematopoietic stem cell by the in vitro colony forming assay. CD34+ myeloid stem cell has been known to express CD40. We speculated by these facts that myeloid cell numbers are regulated by CD40-CD40L interaction.

Structural organization of the gene for CD40 ligand: molecular analysis for diagnosis of X-linked hyper-IgM syndrome.

CD40 ligand (CD40L) on activated T cells plays a crucial role for Ig heavy-chain class switching and the mutation of the gene for this ligand in the X-chromosome causes immunodeficiency with hyper-IgM (X-HIM). We isolated and characterized the human genomic clone for CD40 L to obtain information about the transcriptional regulatory regions of the gene and to develop a molecular diagnostic method for X-HIM patients. The genomic DNA isolated was over 12 kb long containing 5 exons that cover full sequence of mRNA for the ligand. DNA motif analysis based on transcription factor database revealed the presence of a GATA 1 box at around -265 bp. The typical TATA box, CAT site or GC rich region was not found in the 5' flanking region. However, two possible TATA like sequences were found at around -27 and -136 bp. Using the oligonucleotide primers corresponding to the introns, we performed a PCR-SSCP analysis of each exon from a patient with X-HIM syndrome and detected abnormality in exon 5. When sequenced, dinucleotide deletion in this exon was found in the patient and in one X allele of his mother as the only different sequence from that of the control gene. This procedure is simple and could be used for diagnosis of the X-HIM syndrome.

Characterization of a radiation-resistant Acinetobacter.

For characterizing the radiation-resistant Acinetobacter strain FO-1 reported in the previous paper (1980), we investigated the structure of cell wall, the cellular fatty acid composition, and the detailed taxonomic characteristics. The results denoted that the cell division occurred by simple constriction with the formation of a slight septum and the intermediate dense layer between the outer membrane and the plasma membrane was seen, the main components of the cellular fatty acids were oleic acid, palmitic acid, and palmitoleic acid, and that the strain was tolerant to salt and could not produce acids from cellobiose, melibiose, lactose, and ribose.