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Mamoun Younes Mamoun Younes
Professor of Pathology

Office Phone: 202-677-6608
Email: Email
Department: Pathology


  • MD Medicine, Aleppo University, Syria, 1982


  • Research Fellowship (Visiting Fellow): NIH, NIDDK Digestive Disease Branch, Bethesda, MD 1985-1987
  • Residency in Anatomic Pathology: Yale University School of Medicine, New Haven, CT, 1987-1990
  • Gastrointesitnal and Liver Pathology Fellowship: Baylor College of Medicine, Houston, TX, 1990-1992

Mamoun Younes, MD is a nationally recognized gastrointestinal and liver pathologist. Prior to joining GW, he was tenured professor of pathology and gastroenterology and served as the director of the gastrointestinal and liver pathology services and histology and immunohistochemistry laboratories at Baylor College of Medicine and at UTHealth McGovern Medical School in Houston, TX.



Dr. Younes research focus is mainly biomarkers and translational research. Some highlights of his research include:

  1.  p53 protein overexpression in Barrett’s esophagus and correlation with risk of malignant progression.
  2.  Expression of glucose and amino acid transporters (Glut1, Glut3, ASCT1, ASCT2) in benign and malignant human tissues and the clinical significance of their expression in colorectal cancer.
  3. Estrogen receptor beta expression in breast cancer and correlation with response to adjuvant tamoxifen therapy, and also estrogen  receptor beta isoform expression in various digestive system tumors including colon cancer, esophageal cancer, and pancreatic cancer.
  4. Biomarker expression in inflammatory bowel disease and correlation with treatment with biologics (ongoing interest)
  5. Biomarker expression in nonalcoholic fatty liver disease NAFLD/NASH and prediction of risk of progression to hepatocellular carcinoma (ongoing interest).


Surgical Pathology

Centers and Institutes

Regeneron: EoE Pathology Advisory Board 203-2025.


  • GW Cancer Center


Younes M. Effect of intertumoral biomarker heterogeneity on the reliability of biomarker assays in colorectal cancer: Call for a new approach. JCO Precision Oncology 2023; no. 7 e2300113. Published online June 7, 2023. DOI: 10.1200/PO.23.00113

Saulino DM, Chandran A, Ambelil M, Al Salihi S, Conyers J, Ertan A, DuPont AW, Cash BD, Younes M. Colonic Eosinophilia: Clinicopathologic Study of Paired Right and Left Colon Biopsies from 276 Patients. Ann Clin Lab Sci 2023; 53:76-81.

Younes M, Mamilla D, Ko TC, Cao Y. (2023). Overexpression of Gremlin1 in Crohn’s Disease-Associated Bowel Strictures. Ann Clin Lab Sci 2023; 53: 457- 459.

Younes M, Ayush A, DuPont AW, Cash BD, Ertan A. Incomplete intestinal metaplasia of the stomach is more related to bile reflux than chronic gastritis. Ann Clin Lab Sci 2023; 53: 696-700.

Younes M, Zhang L, Fekry B, Eckel-Mahan K. Expression of p-STAT3 and c-Myc correlates with P2-HNF4? expression in nonalcoholic fatty liver disease (NAFLD). Oncotarget 2022; 13:1308-1313.

Younes M, Schueler SA, Borum ML. Histologic evaluation of eosinophilic esophagitis as part of the recently proposed clinical severity index. Gastroenterology 2022; 163:1719-1720 (letter).

Lennerz JK, Pantanowitz L, Amin MB, Eltoum IE, Hameed MR, Kalof AN, Khanafshar E, Kunju LP, Lazenby AJ, Montone KT, Otis CN, Reid MD, Staats PN, Whitney-Miller CL, Abendroth CS, Aron M, Birdsong GG, Bleiweiss IJ, Bronner MP, Chapman J, Cipriani NA, de la Roza G, Esposito MJ, Fadare O, Ferrer K, Fletcher CD, Frishberg DP, Garcia FU, Geldenhuys L, Gill RM, Gui D, Halat S, Hameed O, Hornick JL, Huber AR, Jain D, Jhala N, Jorda M, Jorns JM, Kaplan J, Khalifa MA, Khan A, Kim GE, Lee EY, LiVolsi VA, Longacre T, Magi-Galluzzi C, McCall SJ, McPhaul L, Mehta V, Merzianu M, Miller SB, Molberg KH, Moreira AL, Naini BV, Nosé V, O'Toole K, Picken M, Prieto VG, Pullman JM, Quick CM, Reynolds JP, Rosenberg AE, Schnitt SJ, Schwartz MR, Sekosan M, Smith MT, Sohani A, Stowman A, Vanguri VK, Wang B, Watts JC, Wei S, Whitney K, Younes M, Zee S, Bracamonte ER. Ensuring remote diagnostics for pathologists: an open letter to the US Congress. Nat Med 2022. (letter).

Fekry B, Ribas-Latre A, Van Drunen R, Santos RB, Shivshankar S, Dai Y, Zhao Z, Yoo S-h, Chen Z, Sun K, Sladek FM, Younes M, Eckel-Mahan K. Hepatic circadian and differentiation factors control liver susceptibility for fatty liver disease and tumorigenesis. FASEB 2022; 36: published online August 10, 2022.

Younes M, DuPont AW, Cash BD, Ertan A. Alterations in MAdCAM1-positive mucosal capillaries and integrin a4b7-positive lymphocytes in Crohn's disease treated with anti-TNF? biologics. Ann Clin Lab Sci 2021; 51:678-685.

Chakravarti D, Lee R, Multani AS, Santoni A, Keith Z, Hsu W-H, Chang K, Reyes L, Rashid A, Wu C-J, Li J, Zhang J, Shim HS, Chandra K, Deng P, Spring DJ, Nielsen OH, Riis L, Kelagere K, Blutt SE, Zhang J, YounesM, DuPont A, Thirumurthi S, Vilar E, Estes MK, Colla S, Shroyer N, DePinho RA. Telomere dysfunction instigates inflammation in inflammatory bowel disease. PNAS 2021; 118(29): e2024853118.

Zhang Y, Yang B, Davis JM, Drake MM, Younes M, Shen Q, Zhao Z, Cao Y, Ko TC. Distinct murine pancreatic transcriptomic signatures during chronic pancreatitis recovery. Mediators of Inflammation 2021 published online Article ID 5595464 |

Avila M, Ambelil M, Yong Y, Kurana S, Abraham F, Ertan A, Thosani NC, DuPont AW, Cash BD, Younes M. Lymphocytic esophagitis is not similar to eosinophilic esophagitis except for seasonal variation. Ann Clin Lab Sci 2021; 51:347-351.

Yang B, Davis JM, Gomez T, Younes M, Zhao X, Shen Q, Wang R, Ko TC, Cao Y. Characteristic pancreatic and splenic immune cell infiltration patterns in mouse acute pancreatitis. Cell & Bioscience 2021; 11(1), 28 (published online ahead of print)

Singh K, Pruski M, Bland R, Younes M, Guha S, Thosani N, Maitra A, Cash BD, McAllister F, Logsdon CD, Chang JT, Biley-Lundberg JM. Kras mutation rate precisely orchestrates ductal derived pancreatic intraepithelial neoplasia and pancreatic cancer. Lab Invest (2020).

Davis JM, Cheng B, Drake MM, Yu Q, Yang B, Li J, Liu C, Younes M, Zhao X, Bailey JM, Shen Q, Ko TC, Cao Y. Pancreatic stromal Gremlin 1 expression during pancreatic tumorigenesis. Genes Dis 2020 (published online ahead of print)

Subramanian SK, Patel JM, Younes M, Rubin MIN. Postinfectious autoimmune hepatitis-induced liver failure: A consequence of Hepatitis A virus infection. ACG Case Reports J 2020; 7:e00441.

Tozlu M, Cash B, Younes M, Ertan A. Dilemma in post-IBD symptoms: A 2020 overview. Expert Rev Gastroent & Hepatol 2021; 15:5-8.

Chakravarti D, Hu B, Mao X, Rashid A, Li J, Liao W-t, Whitley EM, Dey P, Hou P, LaBella KA, Chang A, Wang G, Spring DJ, Deng P, Zhao D, Liang X, Lan Z, Lin Y, Sarkar S, Terranova C, Deribe YL, Blutt SE, Okhuysen P, Zhang J, Vilar E, Nielsen OH, Dupont A, Younes M, Patel KR, Shroyer NF, Rai K, Estes MK, Wang YA, Bertuch AA, DePinho RA. Telomere dysfunction activates YAP1 to drive tissue inflammation. Nat Commun 11, 4766 (2020).

Tong YT, Younes M. Intestinal spirochetosis: Case series and review of the literature. Ann Clin Lab Sci 2020; 50:386-390.

Bailey J, Singh K, Pruski M, Polireddy K, Jones N, Chen Q, Yao J, Dar W, McAllister F, Ju C, Eltzschig H, Younes M, Moran C, Karmouty-Quintana H, Ying H. Mst1/2 kinases restrain transformation in a novel transgenic model of Ras driven Non-small cell lung cancer. Oncogene 2020; 39:1152-1164.

Younes M, Rahimi E, DuPont AW, Ly CJ, Ertan A. Anti-TNF-? biologics do not reverse CDX2 downregulation in patients with Crohn’s disease. Ann Clin Lab Sci 2020; 50:172-174.

Younes M, Arora A, Thosani NC, DuPont AW, Ly CJ, Ertan A. Downregulation of estrogen receptor beta1 expression in sessile serrated adenomas. Ann Clin Lab Sci 2019; 49:699-702.

Polireddy K, Singh K, Pruski M, Jones NC, Manisundaram NV, Ponella P, Oullette M, Van Buren G, Younes M, Bynon JS, Dar WA, Bailey JM. Mutant p53R175H promotes cancer initiation in the pancreas by stabilizing HSP70. Cancer Lett 2019; 453:122-130.

Fekry B, Latre AR, Baumgartner C, Mohamed A, Kolonin M, Sladek F, Younes M, Eckel-Mahan K. HNF4?-deficient Fatty Liver Provides a Permissive Environment for Sex-independent Hepatocellular Carcinoma. Cancer Res 2019; 79:5860-5873.

Ambelil M, Saulino DM, Ertan A, DuPont AW, Younes M. The Significance of so-called Equivocal Immunohistochemical Staining for CMV in Colorectal Biopsies. Arch Pathol Lab Med 2019; 143:985-989.

Al Salihi S, Jaitly V, Saulino DM, DuPont AW, Ertan A, Everett JM, Younes M. Pancreatic acinar metaplasia in distal esophageal biopsies is associated with chronic non-steroidal anti-inflammatory drug use. Arch Pathol Lab Med 2019; 143:510-512.

Saulino DM, Younes PS, Bailey JM, Younes M. CRM1/XPO1 expression in pancreatic adenocarcinoma correlates with survivin expression and the proliferative activity. Oncotarget 2018; 9:21289-21295.

Younes M, Ly CJ, Singh K, Ertan A, Younes P, Bailey JM. Expression of estrogen receptor beta isoforms in pancreatic adenocarcinoma. Oncotarget 2018; 9:37715-37720.

Obafemi TF, Yu P, Li J, Davis JM, Liu K, Cheng B, Zhao X, Shen Q, Younes M, Ko TC, Cao Y. Comparable response in male and female mice to cerulein-induced chronic pancreatic injury and recovery. Journal of the Pancreas 2018; 19:223-227.

Younes M, Brown K, Lauwers GY, Ergun G, Meriano F, Schmulen AC, Barrosos A, Lechago J, Ertan A. p53 protein accumulation predicts malignant progression in Barrett’s metaplasia: a prospective study of 275 patients. Histopathology, 2017; 71:27-33.

Bailey JM, Hendley AM, Lafaro KJ, Pruski MA, Jones NC, Alsina J, Younes M, Maitra A, McAllister F, Iacobuzio-Donahue CA, Leach SD. p53 mutations cooperate with oncogenic Kras to promote adenocarcinoma from pancreatic ductal cell. Oncogene 2016; 35:4282-4288.

Hendley AM, Wang YJ, Polireddy K, Alsina J, Ahmed I, Lafaro KJ, Zhang H, Roy N, Savidge SG, Cao Y, Hebrok M, Maitra A, Reynolds AB, Goggins M, Younes M, Iacobuzio-Donahue CA, Leach SD, Bailey JM. p120 Catenin suppresses basal epithelial cell extrusion in invasive pancreatic neoplasia. Cancer Res 2016; 76:3351-3363.

Industry Relationships and Collaborations

This faculty member (or a member of their immediate family) has reported a financial interest with the health care related companies listed below. These relations have been reported to the University and, when appropriate, management plans are in place to address potential conflicts.