Authentication and virological safety results for ETCC001. (A) DNA fingerprinting using STR markers, species-specific PCR evaluation and virology study showed that ETCC001 is of human origin and free from 20 types of virus and mycoplasma contamination. (B) Karyotyping of ETCC001 breast cancer cells. Of 20 metaphases of ETCC001 analyzed, fourteen displayed normal female karyotype (i), four showed trisomy at chromosome 20 (ii and iii), and two exhibited non-clonal numerical abnormalities (trisomy at chromosome 5 and 12, iv and v, respectively). Giemsa/trypsin/Leishman (GTL) banding was used to obtain karyotype. +, presence of a PCR product; -, absence of a PCR product.