Genetic alterations on chromosome 16 and 17 are important features of ductal carcinoma in situ of the breast and are associated with histologic type

We analysed the involvement of known and putative tumour suppressor- and oncogene loci in ductal carcinoma in situ (DCIS) by microsatellite analysis (LOH), Southern blotting and comparative genomic hybridization (CGH). A total of 78 pure DCIS cases, classified histologically as well, intermediately and poorly differentiated, were examined for LOH with 76 markers dispersed along all chromosome arms. LOH on chromosome 17 was more frequent in poorly differentiated DCIS (70%) compared to well-differentiated DCIS (17%), whereas loss on chromosome 16 was associated with well- and intermediately differentiated DCIS (66%). For a subset we have done Southern blot- and CGH analysis. C-erbB2/neu was amplified in 30% of poorly differentiated DCIS. No amplification was found of c-myc, mdm2, bek, flg and the epidermal growth factor (EGF)-receptor. By CGH, most frequent alterations in poorly differentiated DCIS were gains on 8q and 17q22–24 and deletion on 17p, whereas in well-differentiated DCIS amplification on chromosome 1q and deletion on 16q were found. In conclusion, our data indicates that inactivation of a yet unknown tumour suppressor gene on chromosome 16q is implicated in the development of most well and intermediately differentiated DCIS whereas amplification and inactivation of various genes on chromosome 17 are implicated in the development of poorly differentiated DCIS. Furthermore these data show that there is a genetic basis for the classification of DCIS in a well and poorly differentiated type and support the evidence of different genetic routes to develop a specific type of carcinoma in situ of the breast. © 1999 Cancer Research Campaig

Concurrent Oral 9 - Rheumatoid Arthritis: Aetiopathogenesis [OP59-OP64]: OP59. The Value of Interleukin-17 Serum Level in Rheumatoid Arthritis Immunopathogenesis

Background: Interleukin (IL)-17 is the main Th-1 cytokine, produced by activated T-lymphocytes. The potential IL-17 value in rheumatoid arthritis (RA) pathogenesis consists of its independent inflammatory response induction and mediated stimulation of proinflammatory factors synthesis resulting in joint destruction. The aim of study was to determine the role of IL-17 in immuno-inflammatory/autoimmune reactions development and to reveal IL-17 serum level associations with clinical and immunological characteristics of RA. Methods: 50 patients with early RA (disease duration >, Russia), anti-CCP antibodies (Axies-Shield Diagnostic, UK) were revealed using ELISA immunoassay. Results: On the base of IL-17 serum level patients were divided in two groups: group1 (n = 28) were patients with normal IL-17 serum level and group2 (n = 22) were those with high IL-17 serum level. In the group2, the rate of patients' pain assessment by visual analogue scale (67.3 ± 7.2 vs 32.8 ± 4.6; P < 0.001), tender (16.7 ± 2.0 vs 8.4 ± 1.1; P < 0.01) and swollen (12.3 ± 2.3 vs 3.9 ± 0.8; P < 0.01) joint count, DAS28 (5.0 ± 0.4 vs 2.8 ± 0.2 P < 0.01) were significantly higher compare to group1. It was found that in group2 the higher T-lymphocyte amount (CD3) was due to CD4 higher quantity, at the same time CD8 amount was significantly lower (22.2 ± 1.5% vs 28.4 ± 1.7%, P < 0.05) compare to group1. This caused the immunoregulative index increasing and indicated in the lost of autoimmune process regulation, including B-lymphocytes (CD19) activation. The CD154 expression was significantly lower in the group2 (3.4 ± 0.4% vs 10.8 ± 2.8%, P < 0.05) compare to group1. The difference in autoimmune reaction indices wasn't significant between groups except antibody-producing B-lymphocytes (13.7 ± 1.5% vs 8.5 ± 1.0%, P < 0.05) and IgM RF serum level (2.9 ± 0.3 U/ml vs 1.6 ± 0.5 U/ml, P < 0.05), which were significantly higher in group1. The IL-17 level had a positive correlative connections with DAS28 (r = 0.7; P < 0.05), circulative immune complex level (r = 0.38; P < 0.05), anti-CCP antibodies (r = 0.4; P < 0.05), IgM RF (r = 0.41; P < 0.05), CD4 (r = 0.38; P < 0.05) and negative correlative connection with CD8 (r = -0.39; P < 0.05). Conclusions: The importance of IL-17 value in immuno-inflammatory and autoimmune reactions development through T-lymphocytes activation in RA pathogenesis was confirmed. Thus the influence on T-depended immuno-inflammatory reaction products synthesis could be a new therapeutic target of RA patients' management. Disclosure statement: All authors have declared no conflicts of interes

E-cadherin inactivation in lobular carcinoma in situ of the breast: an early event in tumorigenesis.

In breast cancer, inactivating point mutations in the E-cadherin gene are frequently found in invasive lobular carcinoma (ILC) but never in invasive ductal carcinoma (IDC). Lobular carcinoma in situ (LCIS) adjacent to ILC has previously been shown to lack E-cadherin expression, but whether LCIS without adjacent invasive carcinoma also lacks E-cadherin expression and whether the gene mutations present in ILC are already present in LCIS is not known. We report here that E-cadherin expression is absent in six cases of LCIS and present in 150 cases of ductal carcinoma in situ (DCIS), both without an adjacent invasive component. Furthermore, using mutation analysis, we could demonstrate the presence of the same truncating mutations and loss of heterozygosity (LOH) of the wild-type E-cadherin in the LCIS component and in the adjacent ILC. Our results indicate that E-cadherin is a very early target gene in lobular breast carcinogenesis and plays a tumour-suppressive role, additional to the previously suggested invasion-suppressive role

ATBF1 and NQO1 as candidate targets for allelic loss at chromosome arm 16q in breast cancer: Absence of somatic ATBF1 mutations and no role for the C609T NQO1 polymorphism

<p>Abstract</p> <p>Background</p> <p>Loss of heterozygosity (LOH) at chromosome arm 16q is frequently observed in human breast cancer, suggesting that one or more target tumor suppressor genes (TSGs) are located there. However, detailed mapping of the smallest region of LOH has not yet resulted in the identification of a TSG at 16q. Therefore, the present study attempted to identify TSGs using an approach based on mRNA expression.</p> <p>Methods</p> <p>A cDNA microarray for the 16q region was constructed and analyzed using RNA samples from 39 breast tumors with known LOH status at 16q.</p> <p>Results</p> <p>Five genes were identified to show lower expression in tumors with LOH at 16q compared to tumors without LOH. The genes for NAD(P)H dehydrogenase quinone (<it>NQO1</it>) and AT-binding transcription factor 1 (<it>ATBF1</it>) were further investigated given their functions as potential TSGs. <it>NQO1 </it>has been implicated in carcinogenesis due to its role in quinone detoxification and in stabilization of p53. One inactive polymorphic variant of <it>NQO1 </it>encodes a product showing reduced enzymatic activity. However, we did not find preferential targeting of the active <it>NQO1 </it>allele in tumors with LOH at 16q. Immunohistochemical analysis of 354 invasive breast tumors revealed that NQO1 protein expression in a subset of breast tumors is higher than in normal epithelium, which contradicts its proposed role as a tumor suppressor gene.</p> <p><it>ATBF1 </it>has been suggested as a target for LOH at 16q in prostate cancer. We analyzed the entire coding sequence in 48 breast tumors, but did not identify somatic sequence changes. We did find several in-frame insertions and deletions, two variants of which were reported to be somatic pathogenic mutations in prostate cancer. Here, we show that these variants are also present in the germline in 2.5% of 550 breast cancer patients and 2.9% of 175 healthy controls. This indicates that the frequency of these variants is not increased in breast cancer patients. Moreover, there is no preferential LOH of the wildtype allele in breast tumors.</p> <p>Conclusion</p> <p>Two likely candidate TSGs at 16q in breast cancer, <it>NQO1 </it>and <it>ATBF1</it>, were identified here as showing reduced expression in tumors with 16q LOH, but further analysis indicated that they are not target genes of LOH. Furthermore, our results call into question the validity of the previously reported pathogenic variants of the <it>ATBF1 </it>gene.</p

Mutation analysis of the Fanconi anaemia A gene in breast tumours with loss of heterozygosity at 16q24.3

The recently identified Fanconi anaemia A (FAA) gene is located on chromosomal band 16q24.3 within a region that has been frequently reported to show loss of heterozygosity (LOH) in breast cancer. FAA mutation analysis of 19 breast tumours with specific LOH at 16q24.3 was performed. Single-stranded conformational polymorphism (SSCP) analysis on cDNA and genomic DNA, and Southern blotting failed to identify any tumour-specific mutations. Five polymorphisms were identified, but frequencies of occurrence did not deviate from those in a normal control population. Therefore, the FAA gene is not the gene targeted by LOH at 16q24.3 in breast cancer. Another tumour suppressor gene in this chromosomal region remains to be identified. © 1999 Cancer Research Campaig

Recurrent <i>MDM2 </i>Amplification in the Spectrum of <i>HMGA2</i>-Altered Pleomorphic Adenoma, Atypical Pleomorphic Adenoma and Carcinoma Ex Pleomorphic Adenoma

Introduction: Pleomorphic adenoma is the most common neoplasm of the salivary glands. While the overall risk of malignancy is relatively low, a distinct molecular sub-group harboring HMGA2 alterations seems to show an increased risk of malignant progression to carcinoma ex pleomorphic adenoma. Purpose: This study investigates MDM2 amplification in HMGA2-altered pleomorphic adenoma, atypical pleomorphic adenoma, and carcinoma ex pleomorphic adenoma. Methods: In this multicenter, retrospective case series analysis, we examined 37 cases of HMGA2-altered pleomorphic adenoma, carcinoma ex pleomorphic adenoma, and pleomorphic adenoma with atypical features. A total of 18 cases were included from our institutional archives, with 19 additional cases derived from published literature. The cases from our institutes were analyzed for MDM2 amplification using a stepped approach by immunohistochemistry and FISH. Results: Collectively, an MDM2 amplification was present in 27% of pleomorphic adenoma (4 of 15), compared to 78% of carcinoma ex pleomorphic adenoma (14 of 18) (p-value = 0.003). In the group of pleomorphic adenomas with atypical features, an MDM2 amplification was present in 50% of cases (2 of 4). These findings indicate an association between MDM2 amplification and malignancy. Strikingly, a mixed control group of 12 benign and malignant PLAG1-altered neoplasms showed no immunohistochemical staining for MDM2. Conclusion: Immunohistochemical MDM2 expression, including MDM2 amplification, is enriched in the group of HMGA2-altered pleomorphic adenoma, and potentially plays role in malignant progression. This study highlights the importance of recognizing the molecular sub-group of HMGA2-altered pleomorphic adenomas and integrate MDM2 analysis into routine diagnostics to corroborate the cytonuclear atypia in these challenging cases.</p