See also “diagnostic assays” under “diagnostic techniques”
Galleri multi-cancer early detection test (screens for more than 50 different cancers by searching a blood sample for tiny scrps of DNA cast off by cancer cells)
Diagnosis of cancer is of the greatest importance since if cancers can be detected at early , they can often be surgical removed and the patient cured.
Imaging: see outline
Histopathology:
PAP (Papanicolao) smear: have been extremely effective at eradicating cervical cancer. In a PAP test, a collection of cells from the cervix of the uterine is taken and examined under the microscope to look for abnormalities.
Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) has been used in resolving proteins in biological specimens and used to differentiate ovarian, breat, prostate and liver cancers from healthy controls (Zhang, Gynecol Oncol, 102:61-66, 2006).
Look for aberrant levels of specific proteins in Blood/Cell.
For example, the protein CA125 is abnormally expressed with ovarian cancer and PSA is abnormally expressed with prostate cancer.
Density gradient centrifugation:Park (US 13/302678) discloses a method of separating cancer cells in a biological sample such as blood using a ligand which is specific to a surface marker on a target cell. The ligand is attached/bound to a particle and then allowed to specifically bind to a surface marker on a target cancer cell to form a particle target cell complex which will thus have a density difference with other cells and can thereby be separated using the density difference.
Look for specific biomarkers/antigens on Exosomes:
Exosomes are small vesicles that are released into the extracellular environment from a variety of different cells, including tumor cells. An exosome is typically created when a segment of the cell membrane invaginates the exosome which is exocytosed. Exosomes may also be referred to as a microvescile, nanovesicle, vesicle, dexosome, bleb, blebby, prostasome, microparticle, intralumental vesicle, endosomal like vesicles or exocytosed vehicles.
–Isolation of Vesicles with antibodies specific to vesicle biomarker:
Spetzler (US2013/0178383) discloses isolation of a vesicle from a biological sample using a capture agent such as an antibody that binds to a biomarker (examples include CD63) on a vesicle. The binding agent can be bound to particles such as beads and the antibody bound particle is used to isolate the vesicle. In one embodiment, a vesicle having a cancer specific antigen on its surface can be captured using an atnibody specific for the antigen and then the vesicle is detected using that antibody which has been labeled with a fluorescent dye. In an alternative embodiment, once the vesicle is captured with the antibody, the caputred vesicles are then detected using detector antibodies against the same or different vesicle antigens of interest.
Taylor (Molecular Biology, 728, pp. 235-246) disclose protocls for size exlcusion chromatography, magentic beads with anti-EpCAM antibodies and ultracentrifugation for isolation of exosomal components from women diangosed with stage III serous adenocarcinoma of the ovary.
Look for circulating Tumor DNA (ctDNA):
Blood contains cellular componlated DNA within the bloostream originating from various cell types. The portion of the cfDNA in the blood of cancer patients released from tumor cells via apoptosis, necrosis, or active release is commonly refered to as circulating tumor DNA (ctDNA) The ctDNA has gained increasing attention becasue of the potentail to detect early cancer metastases. (Park, “Clinical circulating Tumor DNA testing for Prescision oncology” Cancer Res Treat. 2023; 55(2), 351-366).
Commercial Products:
RaDaR Assay (Neogenomics – Inivata):
Signatera (Natera): is a test which involves tumor tissue sequencing followed by the design of patient-specific panels for sequencing cell-free NA in blood. (see US Patent No: 11,530,454), which covers perfomring whole-exome sequencing or whole-genome sequencing on a tumor sample of the subject to identify a plurality of tumor-specific SNV mutations, targeted multiplex amplification of 10-500 loci from cell-free NA isolated form a plasma sample, and sequencing the resulting amplicons to detect one or more of the tumor specific mutations.
Imagining Techniques:
Electron microscopy (EM) has demonstrated the presence of microvesicles and exosomes isolated from biological fluids of cancer patients. The composition of these vescicles can then be determeined by Western immunoblotting. Dynamic light scattering (DLS) can be used to measure these vesicles in suspension and determine size by light scattered from all vesicles under Brownian motion. The number and size of circulating vesicles has also been investigated using nanoparticle tracking analysis (NTA) where quantum dots are conjugated to anti-tumor antigens (anti-CD63 or anti-Ep-CAM antibodies using a Qdot 585 Antibody Conjugation kit. These conjugates were then added with the vesicles and analyzied by NTA. (Taylor Analytical Biochemistry 428 (2012) 44-53).
Detection of Autoantibodies to Cancer Specific Proteins/Peptides/Antigens
This type of detection method is much like when HIV peptides are detected by looking for whether people have developed antibodies (auto-antibodies) to such peptides.
Taylor (WO 2011/063232) discloses methods for detecting or staging cancer by contacting a sample having IgG type (particularly IgG2 subclass) antibodies with a tumor associated antigen and then detecting the formation of the antibody-antigen complex where the presence of the autoantibodies incidates the presence or stage of cancer. In a separate paper by Taylor (Gynecologic Oncology, 115 (2009) 112-120) a diagnostic array utilized specific exosome dervied antigens to detect reactive IgG in patient’s sera.
Taylor (WO2008/092164) also disclsoes providing a biological sample suspected of comprising autoantibodies from a cancer subject and then contacting that sample with an cancer antigen which is a peptide that has been determined to be immunoreactive with an autoantibody isolated from an exosome from a cancer patient and then detecting the imuno-conjugate as with ELISA or Western blotting.
Antibody or Protein G which binds to Heavy Chain of IgG bound extracellular vesicle
Taylor (US13/795708, published as 2014/0186293; 15/152.901, published as US 2017/0097352) discloses methods of diagnosing cancer by isolating an IgG bound extracellular vesicle. The patent is based on the discovery that IgG binds to tumor antigens on extracellular vesicle in incaner patients. By using an agent such as protein G which binds to the heavy chain contstant domain of IgG, the IgG bound extracellular vesical can be isolated.