Abstract 2926: The effect of cancer research autopsy parameters on DNA and RNA sequencing quality
Authors: Fessas Petros , Hessey Sonya , Richard Corentin , Naceur-Lombardelli Cristina , Ward Sophia , Moore David A. , Nowakowska Karolina , Trujillo Blanca , Lobon Irene , Shepherd Scott T. , Byrne Fiona , Turajlic Samra , Attard Gerhardt , Swanton Charles , Jamal-Hanjani Mariam 
Published: March 2024

Background: Cancer research autopsy genomic studies offer insight into the metastatic cancer landscape but come with complexities that relate to the sampling and processing of post-mortem tissue. Clarifying the effect of autopsy variables on pre- and post-sequencing quality control (QC) is an unmet need that may inform tissue collection strategies.

Methods: The effect of age, sex, post-mortem interval (PMI), and sample type (primary, metastatic, or normal) on pre-sequencing QC (nucleic acid concentration and integrity) was examined in 2678 samples (88.6% metastatic, 8.0% primary, 3.4% normal) from 83 patients with melanoma, lung, renal, or prostate cancer in the PEACE study. In the lung cohort, 160 surgical samples were also included through the TRACERx study, allowing surgery-autopsy tissue comparisons. Post-sequencing QC metrics were evaluated for lung samples that underwent DNA (n=522) or RNA (n=366) sequencing.

Results: RNA concentration and RIN were greater in surgical samples than those collected at autopsy. Across cohorts, metastatic autopsy samples had greater nucleic acid concentrations than primary or normal autopsy samples, but not integrity. DNA and RNA concentration and integrity differed significantly between primary tumor types. When comparing samples of different metastatic sites from the whole cohort, concentration was lowest in bone (DNA) or the digestive tract (RNA), while integrity was greatest in the brain and lowest in the digestive tract (DIN, RIN). Although autopsy variables like age, sex and PMI correlated with pre-sequencing QC metrics in univariate analysis, they were not found to significantly correlate with these metrics in multivariate analysis, which identified that only primary cancer type and metastatic site were independent determinants of concentration and integrity. Similarly, for post-DNA (whole exome) sequencing QC, only the metastatic site was found to independently influence sequencing QC metrics like total number of sequences, average sequence length, and FastQC score. For RNA sequencing, only the metastatic site was found to influence sequencing QC metrics like total number of sequences, percentage of non-duplicated sequences, one hit-one genome percentage, and the alignment percentage on the human genome.

Discussion: The lack of influence of PMI on QC in the largest QC-focused autopsy cancer study to date suggests that quality tissue can be obtained from non-rapid autopsy programs, which are more feasible and less resource-intensive than rapid programs.

Citation Format: Petros Fessas, Sonya Hessey, Corentin Richard, Cristina Naceur-Lombardelli, Sophia Ward, David A. Moore, Karolina Nowakowska, Blanca Trujillo, Irene Lobon, Scott T. Shepherd, Fiona Byrne, Samra Turajlic, Gerhardt Attard, Charles Swanton, Mariam Jamal-Hanjani. The effect of cancer research autopsy parameters on DNA and RNA sequencing quality [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2926.