PER-785 (CVCL_IZ03) — infant t(4;11) line from a child who survived
also called PER-785A · CVCL_IZ03
PER-785 comes from a two-month-old girl with the index fusion who, unusually, was cured and was alive and well in her twenties. Most infant lines in this field come from children who died.
The same thing, for a scientist
PER-785 (CVCL_IZ03) was established from the bone marrow of patient P399, a female infant 66 days old at diagnosis with WBC 670 x10^9/L and CNS1, treated on CCG 1953, who did **not** relapse and was alive without disease at 24 years of age at last follow-up. The diagnostic karyotype was a clean 46,XX,t(4;11)(q21;q23); the line is 47,XX,t(4;11)(q21;q23),+19,der(19)t(1;19)(q12;p13.3), with directed metaphase KMT2A FISH confirming 3' distal KMT2A on der(4) and 5' proximal KMT2A retained on der(11). Immunophenotype: CD19 100%, CD24 100%, CD38 80%, iCD79a 83%, HLA-DR 100%, CD10 <1%, CD34 <1%, with myeloid CD13 74% and CD7 37%. Doubling time 60 h. Cellosaurus records an OI relationship to PER-785S (CVCL_IZ04), a sibling derivative from the same individual, and RNA-seq is deposited.
Why a survivor's line is worth more than its share
Six of the eight Perth infant lines come from children who died or relapsed; PER-785 and PER-910 come from long-term survivors 1. A panel that contains only fatal disease cannot distinguish 'biology of KMT2A::AFF1' from 'biology of KMT2A::AFF1 that resists treatment'. Having a cured patient's line in the same panel, phenotyped the same way, is the internal control that makes a chemosensitivity comparison possible at all.
The primary karyotype here is also the simplest in the panel — a bare 46,XX,t(4;11)(q21;q23) — which matches the known feature of infant KMT2A-rearranged ALL that it carries almost no secondary lesions.
| accession | CVCL_IZ03 |
|---|---|
| resolved by | Cellosaurus accession lookup 2026-09-19; primary name read back as PER-785 |
| age at derivation | 66 days (2 months) |
| infant derived | true |
| sex | Female |
| site | Bone marrow |
| lineage | B-lymphoid pro-B, CD10-negative, CD34-negative, with myeloid CD13 |
| fusion | KMT2A::AFF1, t(4;11)(q21;q23) confirmed by directed metaphase KMT2A FISH |
| karyotype line | 47,XX,t(4;11)(q21;q23),+19,der(19)t(1;19)(q12;p13.3)[20] |
| karyotype patient | 46,XX,t(4;11)(q21;q23)[20] |
| patient outcome | alive without disease, 24 years old at last follow-up |
| same individual as | CVCL_IZ04 (PER-785S) |
| in depmap | false |
| crispr screen published | false |
synonyms
[ "PER-785A" ]
doubling time h
[ 60 ]
- The line carries a secondary der(19)t(1;19) that the patient's leukaemia did not, so any dependency attributed to KMT2A::AFF1 in this line needs the 19q lesion excluded.
- Outcome data attached to a line is retrospective and single-centre; a survivor line invites the inference that its biology is the curable kind, and nothing in the data supports that inference.
- Is PER-785 measurably more chemosensitive in vitro than the lines from children who died? The panel has been drug-screened but the published analyses group the lines rather than contrasting survivor with non-survivor.
- Does the acquired +19/der(19)t(1;19) change the line's dependency profile? t(1;19) is itself a recurrent ALL lesion and its presence in a t(4;11) line is a confound nobody has examined.
- E1established confidence 5 of 5: Multiple independent lines of evidence; treated as settled in the field.paper
PER-785 was established from patient P399, a female infant 66 days old at diagnosis (WBC 670 x10^9/L, CNS1, CCG 1953) with a diagnostic karyotype of 46,XX,t(4;11)(q21;q23), who did not relapse and was alive without disease at 24 years of age; the line is 47,XX,t(4;11)(q21;q23),+19,der(19)t(1;19)(q12;p13.3) with KMT2A FISH confirming the t(4;11), and is CD19 100%, CD24 100%, iCD79a 83%, HLA-DR 100%, CD10 <1%, CD34 <1%, CD13 74%.
Preclinical Evaluation of Carfilzomib for Infant KMT2A-Rearranged Acute Lymphoblastic Leukemia · Cheung LC, de Kraa R, Oommen J, et al. · Frontiers in Oncology 2021What this evidence cannot show
Full text read via PMC (PMC8082024), Tables 1-3. Line karyotyped 2020; primary sample 1996. The line acquired +19 and a der(19)t(1;19) not present in the diagnostic karyotype, so it is not karyotypically identical to the patient's disease. AFF1 was not confirmed by an AFF1-specific probe.
Evidence that argues against this (1)
- A line from a cured patient is a line from a leukaemia that was eliminated in vivo, and the cells that grew out in culture are by definition the ones that could grow without a host. That selection is orthogonal to the selection chemotherapy applied, so the line is not a model of chemosensitive disease in any straightforward sense. Cruickshank MN et al. 2017
- E2established confidence 5 of 5: Multiple independent lines of evidence; treated as settled in the field.database
Cellosaurus accession CVCL_IZ03 records PER-785 as a female human cancer cell line, age at sampling 2 months, derived in situ from bone marrow, disease 'Infant acute lymphoblastic leukemia with MLL rearrangement' (NCIt C122617), with RNA-seq data, a doubling time of 60 h, and a same-individual cross-reference to CVCL_IZ04 (PER-785S).
Cellosaurus cell line PER-785 (CVCL_IZ03) · Bairoch A, et al. (SIB Swiss Institute of Bioinformatics) · Cellosaurus 2025What this evidence cannot show
Fetched by accession 2026-09-19. No gene-fusion annotation; the t(4;11) assignment comes from the founding publication, not from the database record. The 2-month age is Cellosaurus's rounding of 66 days.
Evidence that argues against this (1)
- PER-785 and PER-785S are one individual. Counting the Perth panel as eight lines and eight patients is wrong twice over — PER-494/PER-485 are one child and PER-784/PER-826 are another — so eight lines represent six patients, of whom three carry t(4;11). Bairoch A et al. 2025
- related to →KMT2A::AFF1 (MLL-AF4), t(4;11)(q21;q23)
t(4;11)(q21;q23) confirmed by directed metaphase KMT2A FISH
derived at 66 days of age from a child who survived
Telethon Kids Institute infant ALL panel