# ASCL1

Source: https://onco.cc/targets/ascl1/  
OnCo record `ascl1` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

ASCL1 (Achaete-scute homolog 1) is a protein that switches other genes on and off. The public catalogues list it as a biomarker, and clinical evidence ties its variants to diagnosis, prognosis or drug response. Tied to Atypical teratoid/rhabdoid tumour.

## Summary

Transcription factor that plays a key role in neuronal differentiation: acts as a pioneer transcription factor, accessing closed chromatin to allow other factors to bind and activate neural pathways. Directly binds the E box motif (5'-CANNTG-3') on promoters and promotes transcription of neuronal genes. The combination of three transcription factors, ASCL1, POU3F2/BRN2 and MYT1L, is sufficient to reprogram fibroblasts and other somatic cells into induced neuronal (iN) cells in vitro.

CIViC holds 1 clinical evidence item and 0 assertions across 1 variant.

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: achaete-scute family bHLH transcription factor 1; Achaete-scute homolog 1; ASH1; HASH1; bHLHa46
- Tags: cancer-genes-wave
- Symbol: ASCL1
- Class: transcription
- Biology: Transcription factor that plays a key role in neuronal differentiation: acts as a pioneer transcription factor, accessing closed chromatin to allow other factors to bind and activate neural pathways. Directly binds the E box motif (5'-CANNTG-3') on promoters and promotes transcription of neuronal genes. The combination of three transcription factors, ASCL1, POU3F2/BRN2 and MYT1L, is sufficient to reprogram fibroblasts and other somatic cells into induced neuronal (iN) cells in vitro. Plays a role at early stages of development of specific neural lineages in most regions of the CNS, and of several lineages in the PNS. Essential for the generation of olfactory and autonomic neurons. Acts synergistically with FOXN4 to specify the identity of V2b neurons rather than V2a from bipotential p2 progenitors during spinal cord neurogenesis, probably through DLL4-NOTCH signalling activation. Location: Nucleus (UniProt). Locus 12q23.2 (HGNC).
- Where found: Atypical teratoid/rhabdoid tumour: CIViC evidence names this disease

## Notes

- Written by scripts/fetch-cancer-genes.ts from CIViC, Open Targets, IntOGen, HGNC and UniProt; the function text is UniProt's, condensed and in UK spelling. Roles: CIViC holds 1 clinical evidence items on its variants. Evidence tier "clinical-evidence" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.
- Small-cell lung cancer: ASCL1 is the dominant transcription factor in about 69% of tumours by immunohistochemistry, with 37% co-expressing NEUROD1, a degree of overlap that no laboratory model predicted (Baine 2020). The ASCL1 state is neuroendocrine-marker high, TTF-1 high and DLL3 high, associated with MYCL amplification and with BCL-2 dependence (Rudin 2019, Gay 2021).

## Sources

- HGNC HGNC:738: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:738
- UniProt P50553: https://www.uniprot.org/uniprotkb/P50553/entry
- NCBI Gene 429: https://www.ncbi.nlm.nih.gov/gene/429
- Ensembl ENSG00000139352: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000139352

## Connected records

- collections: [CIViC](https://onco.cc/collections/civic/)
- cancers: [Atypical teratoid/rhabdoid tumour (ATRT)](https://onco.cc/cancers/atrt/), [Small-cell lung cancer](https://onco.cc/cancers/sclc/)
- pathways: [Lineage plasticity & neuroendocrine transformation](https://onco.cc/pathways/lineage-plasticity-neuroendocrine/), [Transcriptional machinery & addiction](https://onco.cc/pathways/transcription-addiction/)
- key papers: [Molecular profiling stratifies diverse phenotypes of treatment-refractory metastatic castration-resistant prostate cancer](https://onco.cc/key-papers/paper-labrecque-mcrpc-phenotypes-jci-2019/), [Molecular subtypes of small cell lung cancer: a synthesis of human and mouse model data](https://onco.cc/key-papers/paper-rudin-sclc-molecular-subtypes-nat-rev-cancer-2019/), [Patterns of transcription factor programs and immune pathway activation define four major subtypes of SCLC with distinct therapeutic vulnerabilities](https://onco.cc/key-papers/paper-gay-sclc-subtypes-inflamed-cancer-cell-2021/), [SCLC subtypes defined by ASCL1, NEUROD1, POU2F3, and YAP1: a comprehensive immunohistochemical and histopathologic characterization](https://onco.cc/key-papers/paper-baine-sclc-subtype-immunohistochemistry-jto-2020/)

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