cyclin-d1 and Hemangiosarcoma

To investigate whether inactivation of the p53 and retinoblastoma (Rb) protein pathways contributes to the development of canine hemangiosarcoma (HSA), we examined immunohistochemically the expression of p53, Rb, phosphorylated Rb (phospho-Rb), p16, and cyclin D1 in 39 spontaneous canine HSAs and 10 hemangiomas. In addition, mutations in the p53 gene were analyzed by polymerase chain reaction (PCR)-single-stranded conformation polymorphism and PCR direct sequencing; furthermore, we quantified cyclin D1 mRNA by semiquantitative real-time reverse transcription-PCR. Positive immunoreactivity for p53 was observed in 17.9% of HSAs. However, mutations were not detected in these cases. The labeling indices for Rb, phospho-Rb, and cyclin D1 were markedly higher in all HSAs than in hemangiomas. Of the 7 cases with cyclin D1-positive immunoreactivity, 4 overexpressed cyclin D1 mRNA (to a level more than 10-fold higher than that of GAPDH mRNA). The p16 protein was clearly detected in all hemangiomas; however, 82% of the neoplastic cells in HSA showed a loss of or low immunoreactivity. These results suggest that alteration of the p16-cyclin D1-Rb pathway, rather than the p53 pathway, may be associated with the pathogenesis of canine HSA.

Topics: Animals; Base Sequence; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p16; DNA Primers; Dog Diseases; Dogs; Hemangiosarcoma; Immunohistochemistry; Molecular Sequence Data; Polymorphism, Single-Stranded Conformational; Retinoblastoma Protein; Reverse Transcriptase Polymerase Chain Reaction; Sequence Analysis, DNA; Signal Transduction; Tumor Suppressor Protein p53

Vascular tumors comprise a minor subgroup of tumors arising in the breast and represent variants of hemangiomas and angiosarcomas. Diagnostic challenges may arise when differentiating hemangiomas from types I and II angiosarcomas. Ki-67 expression has been used as an adjunct to distinguish between benign and malignant lesions exhibiting histologic overlap at various anatomic sites.. To investigate the utility of Ki-67 and other cell cycle regulatory proteins (S-phase kinase-associated protein 2 [Skp2], p27, and cyclin D1) in the differential diagnosis of mammary vascular lesions.. Thirty-four vascular tumors (21 hemangiomas and 13 angiosarcomas) of the breast were studied. The Ki-67 index and immunoreactivity for Skp2, p27, and cyclin D1 were determined in each case. Appropriate statistical methods were used.. The mean value of Ki-67 index was statistically different when comparing hemangiomas and angiosarcomas (P < .001). Angiosarcomas were typically positive for Skp2, whereas hemangiomas were negative (P < .001). Sensitivity and specificity cutoffs for Ki-67 index to distinguish hemangiomas from angiosarcomas showed a candidate cutoff point of 175. The mean values of Ki-67 of low-grade angiosarcomas were significantly different from all hemangiomas (P < .001) and also different from the subset of atypical hemangiomas (P = .02). Sensitivity and specificity cutoffs for Ki-67 index to distinguish all hemangiomas from low-grade angiosarcomas showed a candidate cutoff point between 150 and 175. Among angiosarcomas, positivity for Ki-67 was inversely related to that of p27 but not to Skp2 or cyclin D1. This was also true among hemangiomas.. Ki-67 index can be used as a diagnostic tool to distinguish between benign and malignant vascular lesions of the breast. This can be particularly helpful in cases of histologic overlap such as low-grade angiosarcoma and hemangioma.

Topics: Biomarkers, Tumor; Breast Neoplasms; Breast Neoplasms, Male; Cell Cycle; Cyclin D1; Diagnosis, Differential; Female; Hemangioma; Hemangiosarcoma; Humans; Immunohistochemistry; Ki-67 Antigen; Male; Middle Aged; Proliferating Cell Nuclear Antigen; S-Phase Kinase-Associated Proteins; Sensitivity and Specificity

Topics: Biopsy; Cyclin D1; Endothelial Cells; Gene Expression Regulation, Neoplastic; Granuloma, Pyogenic; Hemangioma, Capillary; Hemangiosarcoma; Humans; Proto-Oncogene Proteins c-akt; STAT3 Transcription Factor; Vascular Diseases; Vascular Neoplasms