title: Myoepithelial carcinoma with RB1 mutation: remarkable chemosensitivity to carcinoma of unknown origin therapy.
abstract: Myoepithelial carcinoma of soft tissue is a rare, malignant neoplasm that is morphologically and immunophenotypically similar to its counterpart in salivary gland. It demonstrates myoepithelial differentiation, possessing both epithelial and myogenic characteristics. Thought to be chemotherapy insensitive, the optimal treatment regimen of this tumor has yet to be established and only a select few cases in the literature discuss treatment efficacy in detail.
  
  
  
  Here we present a case of a young adult with metastatic myoepithelial carcinoma with an initial excellent response to systemic therapy utilizing carboplatin and paclitaxel with continued complete response after 3 years. The patient also underwent complete surgical excision and received adjuvant radiation to the primary site of disease. Exome sequencing revealed an inactivating mutation in RB1 which we believe to be the first such mutation to be reported in this cancer type.
  
  
  
  Given increasing evidence suggesting RB1 loss is associated with responsiveness to conventional chemotherapies, particularly platinum-based regimens, we hypothesize that this genetic feature predisposed chemosensitivity in our patient's tumor.
authors.affiliation: University of South Florida Morsani College of Medicine, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Hoggard
authors.affiliation: Department of Anatomic Pathology, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.|Sarcoma Department, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.
authors.forename: Evita
authors.initials: E
authors.lastname: Henderson-Jackson
authors.affiliation: Department of Anatomic Pathology, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.|Sarcoma Department, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.
authors.forename: Marilyn M
authors.initials: MM
authors.lastname: Bui
authors.affiliation: Department of Diagnostic Imaging, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.
authors.forename: Jamie
authors.initials: J
authors.lastname: Caracciolo
authors.affiliation: Department of Biostatistics and Bioinformatics, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.
authors.forename: Jamie K
authors.initials: JK
authors.lastname: Teer
authors.affiliation: Molecular Genomics Core Facility, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.
authors.forename: Sean
authors.initials: S
authors.lastname: Yoder
authors.affiliation: Sarcoma Department, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.|Adolescent and Young Adult Program; H. Lee Moffitt Cancer Center and Research Institute, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.
authors.forename: Odion
authors.initials: O
authors.lastname: Binitie
authors.affiliation: Sarcoma Department, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.
authors.forename: Ricardo J
authors.initials: RJ
authors.lastname: Gonzalez
authors.affiliation: Sarcoma Department, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Brohl
authors.affiliation: Sarcoma Department, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA. damon.reed@moffitt.org.|Chemical Biology and Molecular Medicine Program, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA. damon.reed@moffitt.org.|Adolescent and Young Adult Program; H. Lee Moffitt Cancer Center and Research Institute, 12901 Bruce B Downs Blvd., Tampa, FL, 33612, USA. damon.reed@moffitt.org.
authors.forename: Damon R
authors.initials: DR
authors.lastname: Reed
mesh_terms: D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D016190:Carboplatin / Q000627:therapeutic use; D006801:Humans; D008297:Male; D009154:Mutation; D009208:Myoepithelioma / Q000235:genetics / Q000628:therapy*; D009362:Neoplasm Metastasis; D017239:Paclitaxel / Q000627:therapeutic use; D018714:Radiotherapy, Adjuvant; D056286:Retinoblastoma Binding Proteins / Q000235:genetics*; D016896:Treatment Outcome; D044767:Ubiquitin-Protein Ligases / Q000235:genetics*
chemical_list: C000606393:RB1 protein, human; D056286:Retinoblastoma Binding Proteins; D016190:Carboplatin; D044767:Ubiquitin-Protein Ligases; D017239:Paclitaxel
keywords: Carboplatin; Chemotherapy; Myoepthelioid carcinoma; Paclitaxel; RB1