title: Digitally guided microdissection aids somatic mutation detection in difficult to dissect tumors.
abstract: Molecular genetic testing on formalin fixed, paraffin embedded (FFPE) tumors frequently requires dissection of tumor from tissue sections mounted on glass slides. In a process referred to as "manual macrodissection," the pathologist reviews an H&E stained slide at the light microscope and marks areas for dissection, and then the laboratory performs manual dissection from adjacent sections without the aid of a microscope, using the marked reference H&E slide as a guide. Manual macrodissection may be inadequate for tissue sections with low tumor content. We compared manual macrodissection to a new method, digitally guided microdissection, on a series of 32 FFPE pancreatic cancer samples. KRAS hotspot mutation profiling was performed using the Sequenom MassARRAY system (Agena Bioscience). Digitally guided microdissection was performed on multiple smaller areas of high tumor content selected from within the larger areas marked for manual macrodissection. The KRAS mutant allele fraction and estimated neoplastic cellularity were significantly higher in samples obtained by digitally guided microdissection (p < 0.01), and 7 of the 32 samples (22%) showed a detectable mutation only with digitally guided microdissection. DNA quality and yield per cubic millimeter of dissected tissue were similar for both dissection methods. These results indicate a significant improvement in tumor content achievable with digitally guided microdissection.
authors.affiliation: Department of Pathology, University of Utah Health Sciences Center, 1950 Circle of Hope, RM N3100, Salt Lake City, UT 84112, USA. Electronic address: katherine.geiersbach@aruplab.com.
authors.forename: Katherine
authors.initials: K
authors.lastname: Geiersbach
authors.affiliation: AvanSciBio LLC, 1290 West 2320 South, Salt Lake City, UT 84119, USA.
authors.forename: Nils
authors.initials: N
authors.lastname: Adey
authors.affiliation: Counsyl, Inc., 180 Kimball Way, South San Francisco, CA 94080, USA.
authors.forename: Noah
authors.initials: N
authors.lastname: Welker
authors.affiliation: Wisconsin State Lab of Hygiene, University of Wisconsin-Madison, 465 Henry Mall, Madison, WI 53706, USA.
authors.forename: Danielle
authors.initials: D
authors.lastname: Elsberry
authors.affiliation: ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108, USA.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Malmberg
authors.affiliation: ARUP Laboratories, 500 Chipeta Way, Salt Lake City, UT 84108, USA.
authors.forename: Sumie
authors.initials: S
authors.lastname: Edwards
authors.affiliation: Department of Pathology, University of Utah Health Sciences Center, 1950 Circle of Hope, RM N3100, Salt Lake City, UT 84112, USA.
authors.forename: Erinn
authors.initials: E
authors.lastname: Downs-Kelly
authors.affiliation: Department of Pathology, University of Utah Health Sciences Center, 1950 Circle of Hope, RM N3100, Salt Lake City, UT 84112, USA.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Salama
authors.affiliation: Department of Pathology, University of Utah Health Sciences Center, 1950 Circle of Hope, RM N3100, Salt Lake City, UT 84112, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Bronner
mesh_terms: D004273:DNA, Neoplasm / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods; D042282:Microdissection / Q000379:methods*; D009154:Mutation; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology*; D016612:Paraffin Embedding / Q000379:methods*; D016707:Tissue Fixation / Q000379:methods*
chemical_list: D004273:DNA, Neoplasm
keywords: Microdissection; digital pathology; formalin fixed paraffin embedded; macrodissection