**Author details**

complex and difficult to interpret, while mitochondrial-based methods may not be effective for species detection if mitochondria from one species are retained preferentially (as is true for the mouse). However, many methods can be optimized to allow for detection of cellcell hybrids. For example, SNP genotyping is increasingly used for cell line authentication and has been used as a test method for patient-derived xenograft models [64]. SNP panels could be modified to include species-specific marker sets, or human and mouse SNP panels could be run in parallel to confirm species and strain identifications and search for additional markers. Although this type of comprehensive assessment is not usually performed, it could be incorporated into testing pipelines if laboratories are aware of the spontaneous (unintentional) cell fusion issue and look specifically for such markers of cell fusion. A role has been suggested for cell-cell fusion in cancer, stem cell plasticity, and trans-differentiation [17–20, 54, 59, 65–67]. A better set of tools is needed to explore hybrid cell lines and the role of somatic

cell hybridization in health and disease.

DNA deoxyribonucleic acid

HLA human leukocyte antigen

NPC nasopharyngeal carcinoma

PCR polymerase chain reaction

SNP single nucleotide polymorphism

SNV single nucleotide variation

STR short tandem repeat

SV40 simian virus 40

RNA ribonucleic acid

HPV human papillomavirus

FISH fluorescence in situ hybridization

HHV-8/KSHV herpesviruses-8/Kaposi sarcoma herpesvirus

HTLV-1 human T-cell lymphotropic virus type 1

RFLP restriction length fragment polymorphism

EBV Epstein-Barr virus

**Abbreviations**

164 Cell Culture

Raymond W. Nims<sup>1</sup> \*, Amanda Capes-Davis<sup>2</sup> , Christopher Korch<sup>3</sup> and Yvonne A. Reid<sup>4</sup>

\*Address all correspondence to: rnims@rmcpharma.com

1 RMC Pharmaceutical Solutions, Inc., Longmont, CO, USA

2 CellBank Australia, Children's Medical Research Institute, The University of Sydney, Westmead, New South Wales, Australia

3 Division of Medical Oncology, University of Colorado Denver, Aurora, CO, USA

4 ATCC, Manassas, VA, USA
