Simulation of a case of identification of human remains using slides employed for oncological diagnosis

SEGUNDO LUGAR: TRABAJO LIBRE SOMETIDO EN LAS XV JORNADAS LATINOAMERICANAS DE GENETICA FORENSE DE LA SLAGF, BOLIVIA 2025

Abstract

Introduction: Identifying missing persons is challenging when the remains are not visually recognizable; therefore, forensic genetics may be used. This process requires a reference DNA sample from the missing person (1). Such a sample can be obtained from personal items that may contain bodily fluids or hair follicles. However, these items may contain DNA from other individuals or may not always be available. Formalin-fixed paraffin-embedded tissues could be an alternative for obtaining a reference genetic profile of the missing person, as they can be preserved for many years (2). These types of samples are commonly used in the diagnosis of diseases such as cancer. However, it has been reported that microsatellite instability, mutations, or chromosomal abnormalities may occur in cancerous tissue, potentially altering the genetic profile (3,4). To evaluate the feasibility of using this type of sample for forensic purposes, we simulated a case of missing person identification using slides prepared for cancer diagnosis.

Methodology: We obtained genetic profiles from a healthy tissue sample (without cancer), a sample containing a mixture of healthy and cancerous tissue, and a sample consisting solely of cancerous tissue, all from a patient diagnosed with ovarian clear cell carcinoma in 2016. These profiles were used as references for the missing person. The samples were compared with the genetic profile obtained from a saliva sample collected from the patient in 2024.

Results: When analyzing the STR markers, we observed that the markers TPOX, SE33, and D2S1338 were not detected in the healthy tissue sample, and the CSF1P0 marker was identified as homozygous, which differs from the other samples. In the mixture of healthy and cancerous tissue, the TPOX marker was not detected, and the SE33 marker was identified as homozygous, which is inconsistent with the profile observed in the other samples. Interestingly, the genetic profiles of the cancer and saliva samples were completely obtained, and all the markers matched, resulting in a positive identification (Table 1).

Discussion and conclusions: In this study, we detected some alterations in the profile of the analyzed cancer sample, such as lower peak intensity compared to the saliva sample. However, the characteristics of this profile were sufficient to allow a positive identification. Our findings suggest that samples used in histopathological diagnosis and archived for several years could serve as reference material for the forensic identification of missing persons, even when they contain cancerous tissue. Further studies are required to elucidate the molecular mechanisms underlying the observations reported here.