Finally had the chance to read the announcement. Yet another Ann...

Finally had the chance to read the announcement. Yet another Ann that screams FTD, BTD and best in class along with recent SARTATE - I would be surprised if we didn’t apply or achieve them.

Huge unmet need in GRPR. This is what our AI friend has to say.

Question: What percentage of cancers and which cancers don’t express PSA but express GRPR?

Great question! To clarify, you’re asking about cancers that do not express PSA (Prostate-Specific Antigen) but do express GRPR (Gastrin-Releasing Peptide Receptor), along with what percentage of cancers fall into that category.

PSA and GRPR Expression Overview

• PSA is primarily a marker for prostate cancer and is highly specific to prostate epithelial cells.
• GRPR is expressed in various cancers, including prostate cancer, but also in some non-prostate cancers.

Cancers That Do NOT Express PSA but Express GRPR

1. Non-Prostate Cancers with GRPR Expression
   PSA is essentially not expressed outside prostate tissue, so non-prostate cancers generally don’t express PSA but can express GRPR.
2. Common cancers known to express GRPR but not PSA include:

• Breast cancer: Many studies show GRPR is overexpressed in breast cancer cells, especially in estrogen receptor-positive subtypes.
• Lung cancer: Both small cell and non-small cell lung cancers can express GRPR.
• Gastrointestinal cancers: Pancreatic, colon, and gastric cancers have shown GRPR expression.
• Bladder cancer: Some bladder cancers express GRPR.
• Gliomas: Certain brain tumors like gliomas express GRPR but not PSA.

Percentage of Cancers Expressing GRPR but Not PSA

PSA expression outside prostate cancer is negligible, so we focus on GRPR:

• Breast cancer: GRPR expression reported in ~60-80% of cases in various studies.
• Lung cancer: GRPR expression seen in ~40-70% of cases.
• Gastrointestinal cancers: Variable, but reports suggest ~30-60% depending on subtype.
• Bladder cancer: Roughly 40-50% express GRPR.
• Gliomas: Up to ~50% show GRPR positivity.

Exact percentages vary depending on detection method (IHC, mRNA), cancer subtype, and study population.

Summary Table

	Cancer Type	PSA Expression	GRPR Expression (%) (approximate)
1	Prostate cancer	High	High
2	Breast cancer	None	60-80%
3	Lung cancer	None	40-70%
4	Gastrointestinal	None	30-60%
5	Bladder cancer	None	40-50%
6	Gliomas	None	~50%