SummaryDendritic cells (DC) are described as "nature's adjuvant," since they have the capacity to sensitize T cells in vivo upon first encounter with the antigen. The potent accessory properties of DC appear to develop sequentially. In particular, the ability to process antigens and to sensitize naive T cells develops in sequence, a process termed "maturation" that is well described in vitro. Here, we obtain evidence for maturation in vivo in response to the bacterial product lipopolysaccharide (LPS). Before LPS treatment, many DC are found at the margin between the red and white pulp. These cells lack the M342 and DEC-205 markers, but process soluble proteins effectively. 6 h after LPS, DC with the M342 and DEC-205 markers are found in increased numbers in the T cell areas. These cells have a reduced capacity to process proteins, but show increases in the B7 costimulator and T cell stimulatory capacity. 48 h after LPS, the number of DC in the spleen is reduced markedly. We interpret these findings to mean that LPS can cause DC in the marginal zone to mature and to migrate into and then out of the T cell areas.

Abstract. Fifty-eight formalin-fi xed par affin-embedd ed canine mammar y tum or s, 19 malignant and 39 benign, were used in th is stud y. T umors were ob tai ned fro m dogs sub mi tte d for surgica l resection of lesions at privat e veterinary pra ctices in Brussels or fro m the su rgery unit of the Fac ulty of Veterinary Med icine, University of Liege. Immunoh isto chem ical eva luation was performed , usin g mon oclon al anti bod ies directed against keratins 8-18 and 19, vime ntin, desmi n, and a -actin and polyclonal anti bod ies directed against high-molecular-weight keratins and S-I 00 protein. Th e main cell types, epithelial, myoepithelial, and connective, were identifi ed , and myoep ith elial cells represent ed the major com po nent of most tum ors, both benign and malignan t. Myoep ith elial cells had five patt ern s: resting and proliferati ve supra basa l cells, spindle and sta r-shaped inters titial cells, and cartilage. Reactivity to keratin 19, vimen tin, a -actin, and S-I00 prot ein suggested a prog ressi ve transformation from resting cells to cartilage. Epithelial cell reac tivities were lim ited to keratins; only keratinized cells were posit ive for polyclonal keratins. Myofibroblasts were positive for both vime ntin and a -actin, and connective tissue cells were posit ive for vi me ntin. Myoepithelial cells appeared to be th e major com po nent of carcino mas , j ustifying reeva luation and sim plification of histomorphologic class ifications, with a " pleomorphic carci no ma" gro up incl uding all carcinomas exce pt squa mo us, mucino us, and comedo carcino ma s. Imm unoh istochem ical evaluation, in add itio n to routine hem atoxylin and eos in histop ath ologic eval uation is recommended for precise classificati on of canine mammary tumors.Key words: Canine species; im m uno histoc hemis try; mamm ar y tum ors ; myoepithelial cells. After skin tumor s, mammary tumors ar e th e seco nd acteriza tio n and histogenesis. ", , · ' 5. ' 9.23,28 Epithe lial cells most frequent neoplasm in dogs ." Malignant tumors express cyto keratin filam ents, mesenchymal cells exocc ur sponta neously in elde rly animals->' or often de-press vimentin filam ents, and mu scle cells express desvelop on ben ign lesions. 2 -4.32 Canine mammary tumors min fila me nts. Ab out 20 d ifferent subtypes of kerat in s a re an exce llent mod el for th e study of human breast ha ve been describ ed acco rd ing to th eir molecular ca ncer. 8 , 16,25 They have sim ilar histol ogic origin and weight, and th ey are characteristically found in certa in comparable regional and systemi c metastasis, and th ey epi the lia. For example, in hum an mamma ry glands, appear in signi ficant number s at a sim ilar relati ve age." epithe lial cells ex press keratins 14 and 18.14 Markers However , freq uency o f th e vario us histologic types is othe r than interme d iate filaments can also be used to d ifferenL ' 7 ,22,26 ide ntify cell types, for exa m ple, a -actin m icrofil am ents Charac teris tica lly, canine mammary tum ors ha ve ...

Purpose: To assess the effect of chromosome 17 copy number on HER-2/neu status determination in breast cancers. Experimental Design: HER-2/neu gene copy and chromosome 17 centromere numbers were evaluated on 893 breast carcinomas using double color fluorescence in situ hybridization (FISH). The net and chromosome 17 corrected (ratio) HER-2/neu copy numbers were compared and related to immunohistochemistry done according to the Food and Drug Administration (FDA)^approved scoring system (0, 1+, 2+, and 3+) as a first screening step in 584 cases. Results: When a ratio z2 was considered as criterion for FISH positivity, 49.3% (440 of 893) of cases showed amplification versus 56.2% (502 of 893) by using a net HER-2/neu gene copy number >4 as a alternative criterion; 14.8% (67 of 453) of cases having a ratio <2 had a net HER-2/neu gene copy number >4 and 1.1% (5 of 440) with a ratio z2 had a net HER-2/neu gene copy number <4. Among discordant cases, 88.8% (64 of 72) were polysomic (>2.25 chromosomes 17/cell) and among polysomic cases, 12.8% (40 of 312) of the low polysomic (2.26-3.75 chromosomes 17/cell) and 36.9% (24 of 65) of the highly polysomic (>3.75 chromosomes 17/ cell) cases showed discordance. In cases with a ratio <2, polysomy 17 incidences were 85.7% (6 of 7) in IHC 3+, 42.4% (79 of 186) in IHC 2+, 33.3% (15 of 45) in IHC 1+, and 29.1% (16 of 55) in IHC 0. Conclusion: A net increase in HER-2/neu gene copy number consecutive to polysomy 17 in the absence of specific gene amplification might lead to a strong protein overexpression in a small subset of breast carcinomas. HER-2/neu status determination by FISH is dependent on the criterion considered for positivity in clinical practice.

Overexpression and amplification of the HER-2 oncogene in patients with breast cancer has correlated with early onset of metastasis, resistance to hormonal therapy and some forms of chemotherapy, and shortened survival. Therefore, evaluation of this putative prognostic or predictive factor seems critical. Because different antibodies are used for the detection of the 185-kd HER-2 oncoprotein, we studied the sensitivity of 3 frequently used antibodies. Immunohistochemistry results were correlated with gene amplification level as assessed by fluorescence in situ hybridization. Protein overexpression was found in 17.2% and 12.5% of cases using antibodies against the external (TAB250) and internal (CB11) domains of the protein, respectively, and in 38.0% of cases using a rabbit polyclonal antibody. Fluorescence in situ hybridization was successful in all 160 tumors, and amplification was found in 37 tumors (23.1%). The monoclonal antibody TAB250 had the lowest misclassification rate, 9.6% (sensitivity, 67%; specificity, 97.5%).