A Single-Center Retrospective Analysis of Kaposi's Sarcoma: Is There a Relationship Between Emmprin/CD147 Expression and Biological Behavior?

OBJECTIVES: Emmprin (CD147/BSG) protein is estimated to play a key role in cell migration and chemoresistance in viral carcinogenesis. However, there are very limited studies investigating the CD147 in the oncogenesis of Kaposi's sarcoma-associated herpesvirus. This study aims to reveal the relationship between CD147 expression with histopathological parameters, disease pattern, and recurrence in Kaposi's sarcoma (KS). METHODS: The study included 67 patients diagnosed with KS between January 1982 and September 2023. Clinical and histopathological features were analyzed retrospectively. HHV-8, CD31, and CD147 expressions were evaluated by immunohistochemistry. RESULTS: Sixteen (24%) female and 51 (76%) male patients with median age of 64 (10-86) were included in the study. CD147 was positive in 57 (85%) cases and associated with nodular pattern (P = .001), presence of solid/fibrosarcomatous area (P = .005), and high mitotic activity (P = .035). The disease relapsed in 17 (27%) of the 63 patients with median 2 (0-12) years follow-up. While a 5-year relapse-free survival was 48.5% in the CD147 diffuse positive group, it was 83.4% in focal positive and 100% in negative cases (P = .029). CONCLUSION: Our study exhibited the relationship between CD147 overexpression and recurrence in KS, but the inhomogeneity of the treatment groups and the small number of patients should also be considered. These findings may provide insight into the pathogenesis of KS and the development of targeted therapies in the future.

EWSR1-PATZ1-rearranged sarcoma: a report of nine cases of spindle and round cell neoplasms with predilection for thoracoabdominal soft tissues and frequent expression of neural and skeletal muscle markers.

The knowledge of clinical features and, particularly, histopathological spectrum of EWSR1-PATZ1-rearranged spindle and round cell sarcomas (EPS) remains limited. For this reason, we report the largest clinicopathological study of EPS to date. Nine cases were collected, consisting of four males and five females ranging in age from 10 to 81 years (average: 49 years). Five tumors occurred in abdominal wall soft tissues, three in the thorax, and one in the back of the neck. Tumor sizes ranged from 2.5 to 18 cm (average 6.6 cm). Five patients had follow-up with an average of 38 months (range: 18-60 months). Two patients had no recurrence or metastasis 19 months after diagnosis. Four patients developed multifocal pleural or pulmonary metastasis and were treated variably by surgery, radiotherapy, and chemotherapy. The latter seemed to have little to no clinical benefit. One of the four patients was free of disease 60 months after diagnosis, two patients were alive with disease at 18 and 60 months, respectively. Morphologically, low, intermediate, and high-grade sarcomas composed of a variable mixture of spindled, ovoid, epithelioid, and round cells were seen. The architectural and stromal features also varied, resulting in a broad morphologic spectrum. Immunohistochemically, the following markers were most consistently expressed: S100-protein (7/9 cases), GFAP (7/8), MyoD1 (8/9), Pax-7 (4/5), desmin (7/9), and AE1/3 (4/9). By next-generation sequencing, all cases revealed EWSR1-PATZ1 gene fusion. In addition, 3/6 cases tested harbored CDKN2A deletion, while CDKN2B deletion and TP53 mutation were detected in one case each. Our findings confirm that EPS is a clinicopathologic entity, albeit with a broad morphologic spectrum. The uneventful outcome in some of our cases indicates that a subset of EPS might follow a more indolent clinical course than previously appreciated. Additional studies are needed to validate whether any morphological and/or molecular attributes have a prognostic impact.

CAMTA1 immunostaining is not useful in differentiating epithelioid hemangioendothelioma from its potential mimickers.

OBJECTIVE: Epithelioid hemangioendothelioma is a rare member of vascular tumors of intermediate malignancy. Recently, presence of t(1;3) translocation and WWTR1/CAMTA1 gene fusion, which enhances CAMTA1 expression, are found to be specific to this tumor. We investigated the CAMTA1 immune expression profile of epithelioid hemangioendothelioma and its potential mimickers using a commercially available CAMTA1 antibody. MATERIAL AND METHOD: Standard whole sections from the formalin fixed, paraffin embedded blocks of 12 epithelioid hemangioendotheliomas, 10 angiosarcomas, 9 epithelioid sarcomas, 8 malignant melanomas, 8 signet ring carcinomas, 7 lobular carcinomas of breast, 2 epithelioid mesotheliomas, 2 rhabdoid tumors and 12 miscellaneous hemangiomas were immunostained for anti-CAMTA1 (ab64119, 1:200; Abcam) after pretreatment with citrate pH 6.0 for 20 minutes using Leica Bond detection kit with DAB chromogen. Strong nuclear CAMTA1 expression was scored for its extent as 'negative' ( < 5% positive), '+1' (5-25% positive), '2+' (25-50% positive) and '3+' ( > 50% positive). RESULTS: In 60 out of 70 cases (86%) either 2+ or 3+ strong nuclear staining was seen. Eighty-three % of epithelioid hemangioendotheliomas, 100% of angiosarcomas, 89% of epithelioid sarcomas, 89% of malignant melanomas, 63% of signet ring carcinomas, 71% of lobular carcinomas of breast, 100% of epithelioid mesotheliomas, 50% of rhabdoid tumors and 100% of hemangiomas were stained. Besides neurons, CAMTA1 expression was also observed in squamous epithelium, skin adnexa, breast lobules, prostate glands, bile ducts, colonic mucosa and gastric pits. CONCLUSION: Epithelioid hemangioendothelioma, its potential morphological mimickers and other benign or malignant vascular tumors showed strong and diffuse CAMTA1 expression, nullifying the potential use of CAMTA1 immunohistochemistry as an adjunct in the differential diagnosis.