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Nikolay K. Popnikolov

Nikolay K. Popnikolov, MD, PhD


Department: Pathology & Laboratory Medicine

Practices: Drexel Pathology


  • MD - Medical University of Sofia, Bulgaria
  • PhD - National Center of Oncology, Sofia, Bulgaria

Postgraduate Training / Additional Certifications

  • Postdoctoral research - University of California, Berkeley
  • Postdoctoral research - Baylor College of Medicine

Nikolay Popnikolov, MD, PhD, is an anatomic and clinical pathologist in Center City Philadelphia. He specializes in surgical pathology and autopsy pathology, and is director of the Immunohistochemistry Laboratory.

Clinical Services

Breast pathology, Gastrointestinal pathology, Tumor pathology, Immunohistochemistry, Tumor markers


  • Surgical Pathology - University of Texas Medical Branch, Galveston


  • Anatomic & Clinical Pathology - University of Texas Medical Branch, Galveston

Nikolay Popnikolov, MD, PhD, is a professor in the Department of Pathology and Laboratory Medicine at Drexel University College of Medicine.

Research Interests

Breast biology and pathology; tumor biology


Selected Publications

"Pregnancy-like hyperplasia with focal atypia arising within a gynecomastic male breast: a case report"
Popnikolov N, Yan J, Mendez AB, lmagawa W
Clin Breast Cancer. 2015; 15(2):e171-5.doi:1O.1016/j.clbc.2014.11.010. Epub 2014 Dec 1, 2014

"Calcifying epithelial odontogenic tumor: case report with immunohistochemical and ultra-structural study and review of literature"
Lin J, Bianchi M, Popnikolov NK, Abaza NA
J Maxillofac Oral Surg, 71: 278-289, 2013

"Association of autotaxin/lysophosphatidic acid receptor axis with aggressiveness and phenotype of human breast carcinoma"
Popnikolov N, Dalwadi B, lmagawa W
Tumour Biol, 33:2237-43, 2012

"Reconstituted normal human breast in nude mice: effect of host pregnancy environment and human chorionic gonadotropin on proliferation"
Popnikolov N,Yang J, Liu A, Guzman RC, Nandi S
J Endocrinol, 168: 487-496, 2007

"Diagnostic utility of p75 neurotrophin receptor (p75NTR) as a marker of breast myoepithelial cells"
Popnikolov N, Cavone S, Schultz P, Garcia F
Mod Pathol, 18: 1535-1541, 2006

"Downregulation of TNF-related apoptosis-inducing ligand (TRAIL)/Apo2L in Barrett's esophagus with dysplasia and adenocarcinoma"
Popnikolov NK, Gatalica Z, Adegboyega PA, Norris BA, Pasricha PJ
Appl Immunohistochem Mol Morphol, 14:161-5, 2006

"Benign myoepithelialtumors of the breast have immunophenotypic characteristics similar to metaplastic matrix producing and spindle cell carcinomas"
Popnikolov N, Ayala AG, Graves K, Gatalica Z
Am J Clin Path, 120: 161-167, 2003

"Loss of mismatch repair proteins in sebaceous tumors of the skin"
Popnikolov N, Gatalica Z, Colome-Grimmer Ml, Sanchez RL
J Cutan Path, 30: 178-184, 2003

"Contrasting roles of p57KlP2 and p21WAF1/ClP1/SDl1 in transplanted human and bovine adrenocortical cells"
Thomas M, Popnikolov NK, Scott C, Smith JR, Hornsby PJ
Exp Cell Res, 266:106-113, 2001

"Prevalence and distinctive biologicalfeatures of flat colorectal adenomas in a North American population"
Saitoh Y, Waxman I, West AB, Popnikolov NK, Gatalica Z, Watari J, Obara T, Kohgo Y, Pastricha PJ
Gastroenterology, 12O:1657-1665, 2001

"Subcutaneous transplantation of bovine and human adrenocortical cells in collagen gel in SCID mice"
Popnikolov NK, Hornsby PJ
Cell Transplant, 8: 617-625, 1999

"Human adrenal androgens. Regulation of biosynthesis and role in estrogen-responsive breast cancer in a mouse model"
Thomas M, Popnikolov N, Wang W, Northrup SR, Chen S, Hornsby PJ
Proceedings, Dept. of Defense Breast Cancer Research Program Meeting, Vol II Genetics and Biology of Breast Cancer, pp 791-792, 1997

"In vivo growth stimulation of collagen gel embedded normal human and mouse primary breast epithelial cells in athymic nude mice"
Popnikolov N, Yang J, Guzman RC, Swanson SM, Thordarson G, Collins G, Talamantes F, Nandi, S
J Cell Physiol, 163: 51-60, 1995

"Reconstituted human normal breast in nude mice using collagen gel or matrigel"
Popnikolov N, Yang J, Guzman RC, Nandi S
Cell Biol Int, 19: 539-546, 1995

"Adenoviral-mediated gene transfer into primary human and mouse mammary epithelial cells in vitro and in vivo"
Yang J, Tsukamoto T, Popnikolov N, Guzman RC, Chen X, Yang JH, Nandi S
Cancer Lett, 98: 9-17, 1995

"Phenotypic characterization of collagen gel embedded normal human primary breast epithelial cells in athymic nude mice"
Yang J, Guzman RC, Popnikolov N, Bandyopadhyay G et al
Cancer Lett, 81:117-127, 1994

"Human breast cancers respond to growth factors in vivo but not in vitro"
Yang J, Popnikolov N, Sakthivel R, Nandi S
Cancer Lett, 85: 13-21, 1994

Contact Information

Practice Office

Drexel Pathology Lab
245 N. 15th Street
Mail Stop 435
Philadelphia, PA 19102
Phone: 215.762.8392
Fax: 215.762.3978