Directed cell migration towards a softer environment is called negative durotaxis. The mechanism and pathological relevance of negative durotaxis in tumor progression still requires in-depth investigation. Here, we report that YAP promotes the negative durotaxis of melanoma. We uncovered that the RhoA-myosin II pathway may underlie the YAP enhanced negative durotaxis of melanoma cells. Acral melanoma is the most common subtype of melanoma in non-Caucasians and tends to develop in a stress-bearing area. We report that acral melanoma patients exhibit YAP amplification and increased YAP activity. We detected a decreasing stiffness gradient from the tumor to the surrounding area in the acral melanoma microenvironment. We further identified that this stiffness gradient could facilitate the negative durotaxis of melanoma cells. Our study advanced the understanding of mechanical force and YAP in acral melanoma and we proposed negative durotaxis as a new mechanism for melanoma dissemination.

Systemic vasculitis involving the breast is a rare clinical condition and may mimic breast cancer or mastitis clinically or radiographically. Here, we report a case of polyarteritis nodosa (PAN) with breast involvement and perform a literature review of published cases of systemic vasculitis affecting the breast to better understand this disorder. We report a case of PAN affecting the right breast in a young woman. A retrospective review was performed by searching Medline, Embase, Web of Science, the Cochrane Library, and Scopus for cases of systemic vasculitis involving the breast written in English up to June 1st, 2018. A 27-year-old woman presented with a painful mass in the right breast was diagnosed as PAN by the biopsy. She was treated with prednisone and methotrexate for 6 months, at which time her condition had stabilized and inflammatory markers had normalized. A total of 66 cases were identified, with granulomatosis with polyangiitis (GPA), giant cell arteritis (GCA), and PAN as the main types. The typical manifestation was mass (79.2%, 53/67) in the breast, and all diagnoses were made by the pathology of the breast biopsy. Glucocorticoid and immunosuppressant were the main therapies, and 74.6% (50/67) patients achieved remission during follow-up. Our case and a literature review of 66 cases of systemic vasculitis involving the breast reveal the importance of tissue biopsy to obtain a definitive diagnosis, because the vasculitis subtype strongly influences prognosis.

Background: CCND1 copy number increase is characteristic of acral melanoma and is useful in distinguishing benign and malignant acral melanocytic lesions. Increase of the gene copy number may result in protein overexpression. This raises the possibility that detection of high expression of cyclin D1 by immunohistochemistry (IHC) may be used as a surrogate for direct evaluation of increase in the CCND1 gene copy number. Methods: We examined increases in CCND1 copy number with fluorescence in situ hybridization (FISH), and examined cyclin D1 protein expression with IHC in 61 acral melanomas. Results: Using FISH, 29 acral melanomas (29/61, 47.5%) showed increase in the CCND1 copy number, including 8 (8/61, 13.1%) which showed low-level increase in the CCND1 copy number and 21 (21/61, 34.4%) with high-level increase in the CCND1 copy number. By analysis of IHC, the median IHC score was 15% (range: 1–80%) in acral melanomas with no CCND1 copy number alteration. In acral melanomas with low-level CCND1 copy number increase, the median IHC score was 25% (range: 3–90%). In acral melanomas with high-level CCND1 copy number increase, the median IHC score was 60% (range: 1–95%). Comparing FISH and IHC, cyclin D1 protein expression level has no corelation with the CCND1 copy number in acral melanomas which have no CCND1 copy number alteration and low-level CCND1 copy number increase (P = 0.108). Cyclin D1 protein expression level correlated positively with CCND1 copy number in acral melanomas with high-level CCND1 copy number increase (P = 0.038). The sensitivity, specificity and positive predictive value of using cyclin D1 IHC to predict CCND1 FISH result was 72.4, 62.5 and 63.6%. Increase in CCND1 copy number was associated with Breslow thickness in invasive acral melanoma. Conclusion: High-level increase in the CCND1 copy number can induce high cyclin D1 protein expression in acral melanomas. However low-level increase and normal CCND1 copy number have no obvious correlation with protein expression. Cyclin D1 IHC cannot serve as a surrogate for CCND1 FISH in acral melanomas.