# KLK2 (kallikrein-2)

Source: https://onco.cc/targets/klk2/  
OnCo record `klk2` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A relative of PSA that stays attached to prostate cancer cells, used as a T-cell engager address by J&J.

## Summary

Human kallikrein-2 (KLK2) is an androgen-regulated serine protease that activates PSA; unlike PSA it is retained on the prostate cell membrane, which makes it a usable address for cell-surface therapies. Expression is nearly universal in prostate cancer and prostate-restricted elsewhere, so a KLK2-directed drug can engage T cells against the tumour with little on-target damage to other tissues. The lead agent is Johnson & Johnson's pasritamig (JNJ-78278343, a KLK2 x CD3 bispecific), which showed low cytokine release and PSA responses in phase 1 and is in phase 3 (KLK2-P3-01) in metastatic castration-resistant prostate cancer. Open questions are whether KLK2 expression persists in neuroendocrine or AR-independent disease and how it compares with PSMA as an engager target. The plain version: KLK2 is a cousin of PSA that stays stuck to cancer cells, so drugs can grab it.

## Fields

- Kind: Target
- Last checked: 2026-09-06
- Tags: t-cell-engager-target
- Symbol: KLK2
- Class: surface-antigen
- Biology: Serine protease activating PSA; androgen-regulated.
- Where found: Prostate cancer (nearly universal)

## Notes

- Prevalence not recorded: no peer-reviewed KLK2 expression series with a stated denominator was found for prostate cancer; 'nearly universal' rests on KLK2 being an androgen-regulated, prostate-restricted gene rather than on a published positivity rate.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/KLK2
- Wikipedia: https://en.wikipedia.org/wiki/KLK2

## Connected records

- cancers: [Prostate cancer](https://onco.cc/cancers/prostate/)
- drugs: [Pasritamig](https://onco.cc/drugs/pasritamig/)

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JSON: https://onco.cc/api/v1/entities/klk2.json