title: Comprehensive characterization of malignant phyllodes tumor by whole genomic and proteomic analysis: biological implications for targeted therapy opportunities.
abstract: BACKGROUND
  Phyllodes tumors are uncommon breast tumors that account for less than 0.5% of all breast malignancies. After metastases develop, the prognosis is poor, with very few patients living more than 1 year. The biology of this unusual cancer is not understood and, consequently, no potential targets for treatments are currently available. There has been an exponential increase in the number of commercially available tumor profiling services. Herein, we report a case of metastatic malignant phyllodes tumor for which a comprehensive molecular analysis was performed by using Clinical Laboratory Improvement Amendments (CLIA)-certified labs, providing new insights into the potential opportunities for molecularly targeted therapies for this extremely rare disease.
  
  
  METHODS
  Next-generation sequencing was performed by using the FoundationOne™ platform (Foundation Medicine, Cambridge, MA). Whole-genome array-based comparative genomic hybridization (array CGH) was performed by using the DNAarray™ (CombiMatrix Diagnostics, Irvine, CA). Immunohistochemical and morphoproteomics analysis were performed at Consultative proteomics®, The University of Texas, UT Health Medical School, Houston,TX (Robert E Brown Lab); Clarient Diagnostics, Aliso Viejo, CA; and Caris Life Sciences Target one, Irving, TX, USA.
  
  
  RESULTS
  Next-generation sequencing showed 3 aberrant genes: activating mutation Q61L on NRAS; inactivating mutations Q504* and K740* on RB1; and TP53 loss. Whole-genome array-based comparative genomic hybridization (array CGH) revealed amplifications of chromosome (chr.) 1 (CKS1B gene), chr. 8 (MYC gene), and chr. 9 (CDKN2A gene) Deletions of chr. 17 (TP53), chr. 10 (GATA3), chr. 11 (FGF4 and CCND1 genes), and chr.22 (PDGFβ). Immunohistochemical analysis for relevant markers showed a positive staining for transducing-like enhancer of split (TLE) 3; secreted protein acidic and rich in cysteine (SPARC) was expressed at 2-3+ in the cytoplasm of the tumors cells, whereas mammalian target of rapamycin (mTOR) was expressed up to 2+ in the nuclei of the tumor cells.
  
  
  CONCLUSIONS
  We describe for the first time an NRAS mutation with concomitant activation of PI3K/Akt/mTOR in phyllodes tumor. We also found markers for sensitivity to taxane-based therapies, especially albumin-bound paclitaxel. Exploring the biology of rare malignancies by CLIA certified labs may be reasonable strategy for the development of targeted treatments.
authors.affiliation: Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, FC8.3038, Box 0455, Houston, TX 77030, USA.
authors.forename: Denis L Fontes
authors.initials: DL
authors.lastname: Jardim
authors.forename: Anthony
authors.initials: A
authors.lastname: Conley
authors.forename: Vivek
authors.initials: V
authors.lastname: Subbiah
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D055028:Comparative Genomic Hybridization; D005260:Female; D020558:GTP Phosphohydrolases / Q000235:genetics; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000556:secondary; D008565:Membrane Proteins / Q000235:genetics; D008875:Middle Aged; D003557:Phyllodes Tumor / Q000235:genetics* / Q000556:secondary; D040901:Proteomics
chemical_list: D008565:Membrane Proteins; D020558:GTP Phosphohydrolases; C579846:NRAS protein, human
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