p27 protein test to predict response to CDK4/6 drugs

Tyrosine phosphorylation of p27Kip1 as a biomarker to identify Cdk4/6 inhibitor response

NIH-funded research Suny Downstate Medical Center · NIH-11235188

A lab test that measures a chemical change on the p27 protein to help predict which people with advanced breast cancer will benefit from CDK4/6 drugs like palbociclib, abemaciclib, or ribociclib.

Quick facts

Grant typeR01 grant
Study typeNIH-funded research
Funding institutionSuny Downstate Medical Center NIH-funded
Lab location1 site (Brooklyn, United States)
Project IDNIH-11235188 on NIH RePORTER

What this research studies

This project is developing a lab assay that detects tyrosine phosphorylation of the p27 protein in tumor tissue as a sign that the CDK4 target is active. Researchers will analyze tumor biopsies and archived patient samples and compare the p27 signal with past responses to CDK4/6 drugs. Laboratory studies in cell models will refine the test and its interpretation. The overall aim is a practical companion diagnostic that can be used before treatment to guide therapy choices.

Who could benefit from this research

Good fit: People with hormone receptor–positive metastatic breast cancer who are about to start or consider CDK4/6 inhibitor treatment would be the main candidates.

Not a fit: Patients whose tumors lack the p27 tyrosine change, those not treated with CDK4/6 inhibitors, or people with cancer types not covered by the study may not gain direct benefit.

Why it matters

Potential benefit: If successful, this test could help doctors give CDK4/6 drugs to patients most likely to benefit and spare others from ineffective treatment and side effects.

How similar studies have performed: Similar biomarker approaches are relatively new: some lab and retrospective clinical data suggest potential, but there is not yet a validated, widely used companion test for CDK4/6 drugs.

Where this research is happening

Brooklyn, United States

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Conditions Breast CancerBreast Cancer Patient
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.