Demonstration of a Gastric Bioptic Specimen Mix-up by Laser Capture Microdissection (LCM) and DNA Fingerprinting

Abstract

We demonstrate here the successful use of laser capture microdissection (LCM) and DNA fingerprinting in the identification of a case of gastric bioptic specimen mix-up. A 70-year-old man, suffering from chronic atrophic gastritis, underwent to a gastric biopsy and received a diagnosis of gastric cancer. In the absence of any clinical evidence of gastric cancer, a specimen mix-up was suspected. LCM was used to retrieve gastric cells from the histologic slide, classified as gastric carcinoma, and suspected to be mislabelled. DNA was extracted from microdissected cells, and a total of 16 different genetic loci were analyzed, using an identity test. Comparison of the results with those obtained using DNA extracted from a control slide, and from patient's saliva, demonstrated a distinct DNA fingerprint pattern in all genetic markers examined, clearly indicating the occurrence of a specimen mix-up. The combined use of LCM and DNA fingerprinting represents the most accurate and sophisticated method available for the identification of specimen mix-up, especially when only the tissue on the suspected slide is available.

Authors' Reply

“…Consistent with the title of our article [ 2] would be the possibility that the nuclear-mediated effect on the mitochondrial function could perhaps be mtDNA haplogroup–specific—but certainly not in the form of the artefactual instabilities, as claimed in those dubious publications (which, however, in one case, have now been explicitly defended [ 3], but unfortunately, without carrying out the necessary “forensic-type” analysis looking into potential sample mixture of the previously analyzed samples [ 4] and without determining whether the patient received blood transfusion before the onset of the disease [ 5]). Rather, some complex susceptibility background for tumorigenesis might be anticipated—in analogy to some mtDNA diseases such as Leber's hereditary optic neuropathy (LHON) [ 6].…”