title: mTOR activity in AIDS-related diffuse large B-cell lymphoma.
abstract: BACKGROUND
  Patients infected with HIV have a significantly increased risk of developing non-Hodgkin lymphomas despite the widespread use of HAART. To investigate mTOR pathway activity in acquired immunodeficiency syndrome (AIDS) related diffuse large B-cell lymphoma AR-DLBCL, we used immunohistochemistry to examine the presence of the phosphorylated 70 ribosomal S6 protein-kinase (p70S6K), an extensively studied effector of mTOR Complex 1 (mTORC1) and the phosphorylated phosphatase and tensin homolog (pPTEN), a negative regulator of mTORC1 pathway.
  
  
  METHODS
  We evaluated tissue samples from 126 patients with AR-DLBCL. Among them, 98 samples were from tissue microarrays (TMAs) supplied by the Aids and Cancer Specimen Resource (ACSR), the remaining 28 samples were from cases diagnosed and treated at the University of California, San Diego (UCSD). The presence of p70S6K was evaluated with two antibodies directed against the combined epitopes Ser235/236 and Ser240/244, respectively; and additional monoclonal anti-bodies were used to identify pPTEN and phosphorylated proline-rich Akt substrate of 40kDa (pPRAS40). The degree of intensity and percentage of cells positive for p70S6K and pPTEN were assessed in all the samples. In addition, a subgroup of 28 patients from UCSD was studied to assess the presence of pPRAS40, an insulin-regulated activator of the mTORC1. The expression of each of these markers was correlated with clinical and histopathologic features.
  
  
  RESULTS
  The majority of the patients evaluated were males (88%); only two cases (1.6%) were older than 65 years of age. We found high levels of both p70S6K-paired epitopes studied, 48% positivity against Ser235/236 (44% in ACSR and 64% in UCSD group), and 86% positivity against Ser240/244 (82% in ACSR and 100% in UCSD group). We observed more positive cells and stronger intensity with epitope Ser240/244 in comparison to Ser235/236 (p<0.0001). The degree of intensity and percentage of cells positive for pPTEN was positively correlated with p70S6K levels (p = 0.016 for 235/236 and p = 0.007 for 240/244). High levels of pPRAS40 were observed in the majority of the cases evaluated (64.3%), but no correlation was found with either pPTEN (p = 0.9) or p70S6K (p = 0.9) levels.
  
  
  CONCLUSIONS
  AR-DLBCL frequently contain p70S6K, a main downstream effector of the mTOR pathway. The presence of p70S6K is positively correlated with pPTEN, an inactive form of PTEN, which makes mTORC1 activated. The presence of p70S6K was independent of HIV viral load or CD4 (+) counts. These results suggest that the mTOR pathway is active in the majority of AR-DLBCL, and p70S6K, particularly the Ser240/244 epitope immunohistochemistry is an excellent surrogate biomarker, which could be used to identify cases expected to be responsive to mTOR inhibitors.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, University of California, San Diego, La Jolla, CA, United States of America.
authors.forename: Sara H
authors.identifier: http://orcid.org/0000-0003-0360-3301
authors.initials: SH
authors.lastname: Browne
authors.affiliation: Division of Infectious Diseases, Department of Medicine, University of California, San Diego, La Jolla, CA, United States of America.
authors.forename: Julio A
authors.initials: JA
authors.lastname: Diaz-Perez
authors.affiliation: Division of Infectious Diseases, Department of Medicine, University of California, San Diego, La Jolla, CA, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: Preziosi
authors.affiliation: Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States of America.
authors.forename: Charles C
authors.initials: CC
authors.lastname: King
authors.affiliation: Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States of America.
authors.forename: George A
authors.initials: GA
authors.lastname: Jones
authors.affiliation: Biostatistics Research Center, Department of Family Medicine and Public Health, University of California, San Diego, La Jolla, CA, United States of America.
authors.forename: Sonia
authors.initials: S
authors.lastname: Jain
authors.affiliation: Biostatistics Research Center, Department of Family Medicine and Public Health, University of California, San Diego, La Jolla, CA, United States of America.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Sun
authors.affiliation: Division of Hematology, Department of Medicine, University of California, San Diego, La Jolla, CA, United States of America.
authors.forename: Erin G
authors.initials: EG
authors.lastname: Reid
authors.affiliation: Division of Clinical Pathology, Department of Pathology, University of California, San Diego, La Jolla, CA, United States of America.|Human Tissue Technology Core, University of California, San Diego, La Jolla, CA, United States of America.
authors.forename: Scott
authors.initials: S
authors.lastname: VandenBerg
authors.affiliation: Division of Clinical Pathology, Department of Pathology, University of California, San Diego, La Jolla, CA, United States of America.
authors.forename: Huan-You
authors.initials: HY
authors.lastname: Wang
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000235:genetics / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000328:Adult; D000368:Aged; D002140:California; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D010766:Phosphorylation; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D046888:Tissue Array Analysis; D055815:Young Adult
chemical_list: C484523:AKT1S1 protein, human; D048868:Adaptor Proteins, Signal Transducing; D012694:Serine; C546842:MTOR protein, human; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D058570:TOR Serine-Threonine Kinases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human