Gregory MacLennan, M.D.

Division Chief of Anatomic Pathology
Director, Pathology Residency Program

Mailing Address:
11100 Euclid Ave.
Cleveland, OH 44106

phone: (216) 844-7452


Dr. Gregory MacLennan earned his M.D. degree from the University of Manitoba, Canada, in 1971. He spent six years training in General Surgery and Urology at Manitoba Affiliated Teaching Hospitals, and followed this with a fellowship in Urodynamics at St. Peter's Hospitals, London, England. From 1978 until 1989, Dr. MacLennan practiced Urology in Grand Forks, N.D. and progressed from Clinical Instructor to Associate Professor of Surgery at the University of North Dakota School of Medicine. In 1989, he returned to Manitoba Affiliated Teaching Hospitals and spent 5 years in Residency and fellowship training in Anatomic Pathology and Cytopathology. In 1994 he began a Fellowship in Surgical and Genitourinary Pathology at Mayo Clinic, Rochester, MN. Following his Fellowship, he joined the staff of the Department of Pathology at CWRU in 1995. Dr. MacLennan is Board certified in both Urology and Anatomic Pathology in both Canada and the United States. Additionally, he is Board certified in Cytopathology. Dr. MacLennan is Professor of Pathology at Case Western Reserve School of Medicine, with secondary appointments in Urology and Oncology. He is the Division Chief of Anatomic Pathology, the Director of the Human Tissue Procurement Facility at University Hospitals of Cleveland, and Director of the Tissue Procurement and Histology Core Facility of the Seidman Cancer Center, and Director of the Pathology Residency Program at UHCMC.


Dr. MacLennan has a particular interest in genitourinary pathology. Much of his time is committed to diagnostic surgical pathology and cytopathology. His research has been predominantly clinically oriented, in collaboration with urologists, oncologists and other pathologists, but has also involved collaborations with basic scientists.

Recent Publications: Peer-Reviewed Articles

Schelling LA, Williamson SR, Zhang S, Yao JL, Wang M, Huang J, Montironi R, Lopez-Beltran A, Emerson RE, Idrees MT, Osunkoya AO, Man YG, MacLennan GT, Baldridge LA, Compérat   E, Cheng L: Frequent TMPRSS2-ERG rearrangement in prostatic small cell carcinoma detected by fluorescence in situ hybridization: the superiority of FISH over ERG immunohistochemistry. Hum Pathol 44: 2227-2233, 2013.

Shukla, S, Bhaskaran N, MacLennan GT, Gupta S. Deregulation of FoxO3a accelerates prostate cancer progression in TRAMP mice. Prostate. 2013 Oct;73(14):1507-17.

Williamson SR, MacLennan GT, Lopez-Beltran A, Montironi R, Tan PH, Martignoni G, Grignon DJ, Eble JN, Idrees MT, Scarpelli M, Cheng L: Cystic partially regressed clear cell renal cell carcinoma: A clinicopathologic study of 27 cases emphasizing distinction from multilocular cystic renal cell carcinoma. Histopathology 63:767-779, 2013.

Marengo SR, Zeise BS, Wilson CG, MacLennan GT, Romani AMP. The Trigger + maintenance model of persistant mild to moderate hyperoxaluria induces oxalate accumulation in non-renal tissues. Urolithiasis. 2013 Nov;41(6):455-66.

Shukla S, Sharma H, Abbas A, MacLennan GT, Fu P, Danielpour D, Gupta S. Upregulation of SATB1 is associated with prostate cancer aggressiveness and disease progression. PloS One. 2013;8(1):e53527. doi: 10.1371/journal.pone.0053527. Epub 2013 Jan 7.

Shukla S, Bhaskaran N, Babcook MA, Fu P, MacLennan GT, Gupta S. Apigenin inhibits prostate cancer progression in TRAMP mice via targeting PI3K/Akt/FoxO pathway. Carcinogenesis. 2014 Feb;35(2):452-60.

Kanwal R, Pandey M, Bhaskaran N, MacLennan GT, Fu P, Ponsky LE, Gupta S. Protection against oxidative DNA damage and stress in human prostate by glutathione S-transferase P1. Mol Carcinog. 2014 Jan;53(1):8-18.

Alexander RE, Montironi R, Lopez-Beltran A, Williamson SR, Wang M, Post KM, Sen JD, Arnold AK, Zhang S, Wang X, Koch MO, Hahn NM, Masterson TA, MacLennan GT, Compérat E, Cheng L. EGFR alterations and EML4-ALK rearrangement in primary adenocarcinoma of the urinary bladder. Mod Pathol 27:107-112, 2014.

Wang L, Williamson SR,  Zhang S, Huang J, Montironi R, Davidson DD, Wang M, Yao JL, Lopez-Beltran A, Osunkoya AO, MacLennan GT, Baldridge LA, Du X, Cheng L: Increased androgen receptor gene copy number is associated with TMPRSS2-ERG rearrangement in prostatic small cell carcinoma. Mol Carcinog. 2014 Apr 29. doi: 10.1002/mc.22162. [Epub ahead of print]

Babcook MA, Shukla S, Fu P, Vazquez EJ, Puchowicz MA, Molter JT, Oak CZ, Flask CA, MacLennan GT, Lindner DJ, Parker Y, Daneshgari F, and Gupta S. Synergistic simvastatin and metformin combination chemotherapy for osseous metastatic castration-resistant prostate cancer. Mol Cancer Ther. 2014 Oct;13(10):2288-302.

Iczkowski KA, Egevad L, Harding-Jackson…MacLennan GT,…. et al. Intraductal carcinoma of the prostate: interobserver reproducibility survey of 39 urologic pathologists. Ann Diagn Pathol. 2014 Sep 3. pii: S1092-9134(14)00082-3. doi: 10:1016/janndiagpath.2014.08.010. [Epub ahead of print]

Choi E, Williamson SR, Montironi R, Zhang S, Wang M, Eble JN, Grignon DJ, Lopez-Beltran A, Idrees MT, Baldridge LA, Scarpelli M, Jones CL, Wang L, MacLennan GT, Osunkoya AO, Cheng L: Inflammatory Myofibroblastic tumor of the urinary bladder: the role of IgG4 and the comparison of two immunohistochemical antibodies and fluorescence in situ hybridization for the detection of ALK alterations. Histopathology. DOI 10.1111/his.12619

Simper NB, Jones CL, MacLennan GT, Montironi R, Williamson SR, Osunkoya AO, Wang M, Zhang S, Grignon DJ, Eble JN, Tran T, Wang L, Baldrige LN, Cheng L: Basal Cell Carcinoma of the Prostate is an Aggressive Tumor with Frequent Loss of PTEN Expression and Overexpression of EGFR.  Hum Pathol (in press).

Alwithanani N, Bissada NF, Joshi N,Bodner D, Demko C, MacLennan GT, Skillicorn R, Ponsky L, Gupta S. Periodontal treatment improves prostate symptoms and lowers serum PSA in men with high PSA and chronic periodontitis. OMICS Biomedical Journals-Dentistry. (In press.)

Fu X, Patel D, Zhu H, MacLennan GT, Wang YT, Jenkins MW, Rollins AM. Miniature forward- viewing common-path OCT probe for imaging the renal pelvis. Biomedical Optics Express (in press).

Recent Publications: Book Chapters

Zhang S, Davidson DD, Montironi R, Lopez-Beltran A, MacLennan GT, Cheng L. Conceptual evolution in cancer biology. In: Cheng L, Zhang DY, eds. Molecular Genetic Pathology (2nd edition). New York: Springer (in press).

Williamson SR, Lopez-Beltran A, Zhang S, MacLennan GT, Montironi R, Cheng L: Chapter 6: Immunological & Molecular Studies in Kidney Tumors. In Albitar MX (ed): Immunological & Molecular Diagnosis of Cancer. Page 177-192. Nova Science Publishers, Hauppauge, NY, 2011.

MacLennan GT, Cheng L. Tumors of the kidney. In: Cheng L and Bostwick DG, eds. Essentials of Anatomic Pathology (3rd edition). New York: Humana Press/Springer. 2011: 1487-1514.

MacLennan GT, Larchian WA, Cheng L, Bodner DR, Hardin BM, Goldman HB, Cherullo EE, Ponsky LE. Correlative pathologic features of endoscopically identified lesions of bladder, urachus and urethra. In: Hansel DE, McKenney J, Stephenson AJ, Chang S, eds. The Urinary Tract: A Comprehensive Guide to Patient Diagnosis and Management. Springer-Verlag (in press).

Cheng L, MacLennan GT, Lopez-Beltran A: Histologic grading of urothelial carcinoma. In Damjanov I, Fan F (eds) Cancer Grading Manual (2nd edition). New York, NY: Springer, 2013 (in press).

MacLennan GT, Cheng L:  Chapter 2: Neoplasms of the Kidney. In Bostwick DG, Cheng L (eds) Urologic Surgical Pathology (3rd ed). Page 74-157, Elsevier New York, New York, NY, 2014.

Cheng L, Lopez-Beltran A, MacLennan GT, Montironi R, Bostwick DG. Chapter 6: Neoplasms of the Urinary Bladder. In Bostwick DG, Cheng L (eds) Urologic Surgical Pathology (3rd ed). Page 228-317, Elsevier New York, New York, NY, 2014.

Cooney MM, MacLennan GT and Okuku F.  Global Perspectives on Cancer. Incidence, Care and Experience.  Editors Kenneth D. Miller and Miklos Simon. Chapter on Genitourinary Cancers, Volume 2, Chapter 11 pages 205-234. Praeger Publishing, Copyright 2015.

Recent Publications: Books

Bostwick DG, MacLennan GT, and Larson TR.  Prostate cancer:  What every man - and his family - needs to know.  The American Cancer Society.  New York: Villard Press. 1996. (Revised edition 1999).

MacLennan GT, Resnick MI, and Bostwick DG. Pathology for Urologists. Philadelphia: W. B. Saunders Company. 2003.

MacLennan GT, Cheng L. Atlas of Genitourinary Pathology. Springer-Verlag London Limited 2011.

MacLennan GT. Hinman’s Atlas of UroSurgical Anatomy, 2nd edition. Elsevier, Philadelphia. 2012.

Dogra VS and MacLennan GT (Eds). Genitourinary Radiology: The Pathologic Basis. Volume I: Kidney, Bladder and Urethra. Springer, London. 2013.

Dogra VS and MacLennan GT (Eds). Genitourinary Radiology: The Pathologic Basis. Volume II: Male Genital Tract, Adrenal and Retroperitoneum. Springer, London. 2013