Recurrent targetoid hemosiderotic hemangioma in a 26-year-old man.

A 26-year-old previously healthy man presented with a 6-mm violaceous papule that had a surrounding 1.5-cm annular, nonblanching, erythematous halo on the right-sided flank. The man reported the lesion had been recurring for 4 to 5 years, flaring every 4 to 5 months and then slowly disappearing until the cycle recurred. Targetoid hemosiderotic hemangioma was clinically diagnosed. The lesion was removed by means of elliptical excision and the condition resolved. The authors discuss the clinical appearance, histology, and etiology of targetoid hemosiderotic hemangiomas.

Prepatellar septic bursitis: a case report of skin necrosis associated with open bursectomy.

Patients with prepatellar septic bursitis are typically successfully managed nonoperatively with rest, compression, immobilization, aspiration, and antibiotics. Rarely, surgical excision of the bursa may be required for recalcitrant cases. Prepatellar bursectomy, however, has been associated with considerable risk of surgical-site morbidity. Although skin necrosis is frequently cited as a complication of open bursectomy, there is limited information in the medical literature on the etiology and management of this rare but serious complication.

Novel surface expression of reticulocalbin 1 on bone endothelial cells and human prostate cancer cells is regulated by TNF-alpha.

An unbiased cDNA expression phage library derived from bone-marrow endothelial cells was used to identify novel surface adhesion molecules that might participate in metastasis. Herein we report that reticulocalbin 1 (RCN1) is a cell surface-associated protein on both endothelial (EC) and prostate cancer (PCa) cell lines. RCN1 is an H/KDEL protein with six EF-hand, calcium-binding motifs, found in the endoplasmic reticulum. Our data indicate that RCN1 also is expressed on the cell surface of several endothelial cell lines, including human dermal microvascular endothelial cells (HDMVECs), bone marrow endothelial cells (BMEC), and transformed human bone marrow endothelial cells (TrHBMEC). While RCN1 protein levels were highest in lysates from HDMVEC, this difference was not statistically significant compared BMEC and TrHBMEC. Given preferential adhesion of PCa to bone-marrow EC, these data suggest that RCN1 is unlikely to account for the preferential metastasis of PCa to bone. In addition, there was not a statistically significant difference in total RCN1 protein expression among the PCa cell lines. RCN1 also was expressed on the surface of several PCa cell lines, including those of the LNCaP human PCa progression model and the highly metastatic PC-3 cell line. Interestingly, RCN1 expression on the cell surface was upregulated by tumor necrosis factor alpha treatment of bone-marrow endothelial cells. Taken together, we show cell surface localization of RCN1 that has not been described previously for either PCa or BMEC and that the surface expression on BMEC is regulated by pro-inflammatory TNF-alpha.

Stromal factors involved in prostate carcinoma metastasis to bone.

BACKGROUND: Prostate carcinoma (PC) frequently metastasizes to bone, where it causes significant morbidity and mortality. Stromal elements in the primary and metastatic target organs are important mediators of tumor cell intravasation, chemoattraction, adhesion to target organ microvascular endothelium, extravasation, and growth at the metastatic site. METHODS: The role of stromal factors in bone metastasis was determined with a cyclic DNA microarray comparison of a bone-derived cell PC cell line with a soft tissue-derived cell PC cell line and by evaluating the effects of selected stromal components on PC cell chemotaxis, cell adhesion to human bone marrow endothelium (HBME), and PC cell growth. RESULTS: The authors demonstrate that PC cells express protease-activated receptor 1 (PAR1; thrombin receptor), and its expression is up-regulated in PC compared with normal prostate tissue. In addition, this overexpression was very pronounced in bone-derived PC cell lines (VCaP and PC-3) compared with soft tissue PC cell lines (DUCaP, DU145, and LNCaP). The authors report that bone stromal factors, including stromal cell-derived factor 1 (SDF-1) and collagen Type I peptides, are chemoattractants for PC cells, and they demonstrate that some of these factors (e.g., extracellular matrix components, transforming growth factor beta, bone morphogenic proteins [BMPs], and SDF-1) significantly alter PC-HBME interaction in vitro. Finally, stromal factors, such as BMPs, can regulate the proliferation of PC cells in vitro. CONCLUSIONS: Soluble and insoluble elements of the stroma are involved in multiple steps of PC metastasis to bone. The authors hypothesize that PAR1 may play a central role in prostate tumorigenesis.

A functional thrombin receptor (PAR1) is expressed on bone-derived prostate cancer cell lines.

OBJECTIVES: To identify genes important in prostate cancer metastatic to bone. Bone-specific metastasis is a common feature of prostate cancer and a significant cause of morbidity. METHODS: To identify factors involved in organ-specific metastasis, we used cDNA microarray analysis to compare a bone-derived cell line, VCaP, with a soft tissue-derived cell line, DuCaP. Both cell lines were derived from the same patient and spontaneously passaged. RESULTS: Forty-five genes were differentially expressed, and only seven of these also had increased expression in VCaP compared with normal prostatic tissue. Of these, protease-activated receptor 1 (PAR1) was verified as having increased expression by reverse transcriptase-polymerase chain reaction and Northern blot analysis, as well as by immunohistochemistry. PAR1 expression in a panel of prostate cancer cell lines demonstrated increased expression in those cell lines derived from bone metastases. Alpha-thrombin stimulation of the VCaP cells produced a dose-dependent mobilization of intracellular calcium compared with DuCaP, suggesting that PAR1 expressed on the VCaP prostate cancer cell line is functional. CONCLUSIONS: These data indicate that a functional PAR1 is expressed on prostate cancer cell lines. The prostate cancer cell lines expressing PAR1 appear to have an association with increased bone metastases.