Identification of Biological Samples in a Case of Contamination of a Cytological Slide Preparation*

Abstract

Here we report a case where a discrete section of the cytological slide preparation of a female individual was obviously contaminated with pleura liquid of a female tumor patient. Analysis of the cancerous pleura liquid and the healthy cells of the slide preparation showed different DNA profiles, indicating that the material originated from two different female individuals. The DNA profile of the cell mixture revealed a heterogenous pattern whereby the alleles could be assigned to the healthy and the tumor patient. Loss of heterozygosity (LOH) was observed in four of eight short tandem repeat systems for the pleura liquid and the cell mixture. Despite the low amount of DNA on the slide preparation and the occurrence of LOH, it was possible to clarify the case and to support the assumption that a drop of cancerous pleura liquid contaminated the cytological slide.

Molecular pathology in forensic medicine—Introduction

“…1). One task has already been mentioned -identification -not only regarding paternity testing and stain analysis, but also specimen identification which is carried out on tissue [36,37,63]:…”

“…-for instance identification of biological samples in cases of contamination of cytological slides with cells from different persons [36]; -do different body parts in criminal dismembering of bodies belonging to the same person [63]; -do biopsies belong to one or different persons. In a case of criminal dismemberment of a body several body parts were found over a period of 7 years (Figs.…”

Identification of tumor specimens by DNA analysis in a case of histocytological paraffin tissue block swapping

“…DNA profiling and result interpretation with these samples often becomes a challenging job. The malignant tissues may show preferential amplification, loss of heterozygosity, and microsatellite instability (5,6). Invasive breast cancers, like other malignancies, show microsatellite instability.…”