Detection and therapy are global issues
GASP-1 as a proxy for cancer progression
Using our patented 2-D HPLE technology, we have identified a cancer biomarker called G-Protein Coupled Receptor-Associated Sorting Protein 1 (GASP-1). GASP-1 regulates several G-Protein Coupled Receptors (GPCRs) that are required for cell growth. When GASP-1 is overexpressed, it causes recycling of these GPCRs back to plasma membranes rather than directing them to lysosomes for destruction. Recycling of GPCRs enhances and potentiates the effects of growth factors, thus promoting continuous growth. Cancer cells overexpress GASP-1 in order to achieve faster and sustained growth rate.
Unexpectedly, we found that cancer cells lose the ability to destroy the overproduced GASP-1. Continuous accumulation of GASP-1 leads to their aggregation in the cytosol and forms granules of various sizes ranging from powdery, fine, and coarse granules depending on cancer progression stages. Furthermore, attachment of many large GASP-1 granules to cancer plasma membranes significantly weakens cell-cell interactions, leading to disintegration of plasma membranes and release of GASP-1 into circulation. This may represent a novel method for cancer spreading and metastasis. Thus, GASP-1 overexpression is involved in every stage of cancer development and GASP-1 overexpression can be used for early cancer detection, for assessing cancer severity, for differentiating benign tumor from cancer, and for monitoring cancer treatment.
Diagnostic Applications
Early Detection of Cancers
Early cancer detection not only saves lives but also medical costs and is an major unmet medical need. Liquid biopsy (next generation sequencing of circulating tumor DNA) has been promoted as a new method for early detection of cancers. However, despite all efforts conducted by liquid biopsy companies, their tests have a very low sensitivity for detecting early cancers (less than 20% for Stage I and 40% for Stage II cancers). Because overexpression of GASP-1 starts when normal cells are transformed into cancerous cells, our GASP-1 biomarker is much more sensitive than currently used liquid biopsy tests. We can detect very early-stage cancers with 100% sensitivity and early-stage cancers with similar sensitivity.
GASP-1 IHC can be used to detect early cancer. Halcyon Diagnostics can also manufacture a Rapid GASP-1 IHC kit using either fine needle aspirates or tissue biopsy samples. The Rapid GASP-1 IHC kit takes 10 to 15 min to perform, allowing patients to know their cancer results while in doctor’s office rather than waiting for days. In addition to high sensitivity, our Rapid GASP-1 IHC test is less expensive and can also be used to verify the results of liquid biopsy or other tests.
Assessing cancer severity and differentiating benign tumor from cancer
As indicated earlier, GASP-1 overexpression is involved in cancer initiation and is required for both cancer progression and cancer invasion for all the cancers. Once cancer cells overproduce GASP-1, they cannot be removed. Being sticky in nature, overproduced GASP-1 start to aggregate in the cytosol and form granules of at least three different sizes: powdery, fine, and coarse granules. The size of GASP-1 granules is an indication of cancer severity. As cancer becomes more invasive, GASP-1 granules begin to attach to plasma membranes and also attached to nuclear membranes in advanced or metastatic cancers. We can use the extent of GASP-1 production, their sizes, location, and distribution to assess cancer severity.
Unable to differentiate benign tumor from cancer has resulted in many unnecessary surgeries in cancers. For example, when a nodule is detected in the thyroid gland, the only way to assess whether it is cancerous or not currently is through surgical removal of thyroid gland for immunohistochemical analysis looking for capsular invasion. Our GASP-1 IHC can clearly differentiate benign tumor from cancer and also assessing cancer severity. The same situation also happens to breast and other cancers. By differentiate benign tumor from cancer, our GASP-1 IHC can reduce many unnecessary surgeries.
GASP-1 ELISA for detecting cancer and for monitoring effectiveness of cancer treatment
As cancer progresses, more GASP-1 are produced and released into circulation and are detected by GASP-1 ELISA. Preliminary results showed that GASP-1 ELISA differentiates normal individuals from cancer patients for the following cancers: breast, lung, prostate, pancreatic, liver and glioblastoma. GASP-1 ELISA can also be used to monitor the effectiveness of cancer treatment.
GASP-1 ELISA for differentiate BPH from prostate cancer
Because serum PSA level is elevated in patients with either BPH (benign Prostatic hyperplasia) and/or prostate cancer, for these patients with high serum PSA levels it is commonly recommended to undergo a prostate biopsy to make sure the tumor is benign. Because BPH is a benign condition, we found that in individuals with BPH, their serum GASP-1 level is low and very close to those of normal individuals. On the other hand, when prostate cancer occurs, the serum GASP-1 level becomes significantly elevated. Our GASP-1 ELISA differentiates BPH from prostate cancer. Thus, only individuals having high serum levels of both PSA and GASP-1 are candidates for prostate biopsy. This would spare those individuals with high serum levels of PSA but low GASP-1 from unnecessary biopsy.
Normal breast cells
IHC image of normal breast tissue
Hyperplasia
GASP-1 starts to overexpress on ER
Hyperplasia
GASP-1 are released into the cytosol