Mammary Analogue Secretory Carcinoma of Salivary Glands. (May 2015)

• Record Type: Journal Article
• Authors: Ito, Yohei; Ishibashi, Kenichiro; Masaki, Ayako; Fujii, Kana; Fujiyoshi, Yukio; Hattori, Hideo; Kawakita, Daisuke; Matsumoto, Manabu; Miyabe, Satoru; Shimozato, Kazuo; Nagao, Toshitaka; Inagaki, Hiroshi
• Is Part Of: American journal of surgical pathology. Volume 39:Number 5(2015)
• Publication Date: 2015-05
• Subjects: Pathology, Surgical -- Periodicals; 617.0705
• DOI: 10.1097/PAS.0000000000000392
• Languages: English
• ISSNs: 0147-5185

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <p>Mammary analogue secretory carcinoma (MASC) is a recently described low-grade carcinoma with morphologic and genetic similarity, including <italic>ETV6-NTRK3</italic> fusion, to secretory carcinoma of the breast. <italic>ETV6</italic> is frequently involved in other epithelial and nonepithelial tumors, and many fusion partners of <italic>ETV6</italic> have been reported. In the present study, 14 Japanese MASC cases were clinicopathologically and molecularly analyzed. The median age of the patients was 39 years, and the male:female ratio was 6:8. All cases showed histopathologic findings compatible with those previously described for MASC and harbored an <italic>ETV6</italic> split as visualized by fluorescence in situ hybridization. Two cases showed thick fibrous septa and invasive features including vascular or perineural tumor involvement, findings that are rare in MASC. In addition, in these 2 cases, <italic>non-NTRK3</italic> genes appeared to fuse with <italic>ETV6</italic> (<italic>ETV6-X</italic> fusion). <italic>NTRK1</italic> and <italic>NTRK2</italic>, both members of the <italic>NTRK</italic> family, were not involved. Of the 14 MASC cases, the <italic>ETV6-NTRK3</italic> fusion transcript was positive in 6 cases, and the relative expression level of the <italic>ETV6-NTRK3</italic> fusion transcript was variable, ranging from 1 to 5.8. Results of the present study of MASC suggest that (1) <italic>ETV6</italic> occasionally fuses with unknown <italic>non-NTRK3</italic> genes, (2) <italic>ETV6-X</italic> cases might have an invasive histology, (3) for molecular diagnosis of MASC, fluorescence in situ hybridization to detect <italic>ETV6</italic> splits is the method of choice, and (4) the expression level of the <italic>ETV6-NTRK3</italic> fusion transcript is considerably variable. These findings provide a novel insight into the oncogenesis, histopathology, diagnosis, treatment, and prognosis of this newly recognized carcinoma.</p> </sec> </abstract>