# CD34

Source: https://onco.cc/targets/cd34/  
OnCo record `cd34` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

CD34 marks the blood-forming stem cells that a transplant is counted in, and it also stains blood vessels, which is how new vessel growth in a tumour is measured.

## Summary

CD34 is a sialomucin carried by haematopoietic stem and progenitor cells and by vascular endothelium. It is one of the few markers with a direct clinical count attached: a stem cell graft is dosed in CD34-positive cells per kilogram, which decides whether an autologous or allogeneic transplant can go ahead. Its second use is as an endothelial stain for measuring microvessel density, the standard histological read-out for angiogenesis in a tumour.

## Fields

- Kind: Target
- Last checked: 2026-10-16
- Tags: immune-marker
- Symbol: CD34
- Class: surface-antigen
- Biology: Sialomucin adhesion molecule on haematopoietic stem and progenitor cells and on vascular endothelium.
- Where found: Haematopoietic stem and progenitor cells; Vascular endothelium

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/CD34
- HGNC:1662: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:1662

## Connected records

- targets: [PTPRC](https://onco.cc/targets/ptprc/)
- terms: [Angiogenesis](https://onco.cc/terms/angiogenesis/)
- technologies: [Autologous stem cell transplant (high-dose therapy)](https://onco.cc/technologies/autologous-stem-cell-transplant/)

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JSON: https://onco.cc/api/v1/entities/cd34.json