Compositions and methods for detecting plectin-1 as a biomarker for cancer

1. A method for detecting cancer, diagnosing cancer, monitoring the progression of cancer, or monitoring treatment of a cancer, wherein cells of said cancer express Plectin-1 or a homolog or fragment thereof, said method comprising administering to a test subject a pharmaceutical composition comprising a tetrameric peptide ligand complex, wherein said tetrameric peptide ligand complex comprises an imaging agent, wherein said tetrameric peptide ligand complex has the formula (βAKTLLPTPGGS (SEQ ID NO: 3)(PEG5000)) 4 KKKK(SEQ ID NO: 23)DOTAβA-NH2, detecting said imaging agent and determining the levels and location of said imaging agent in said test subject and comparing said levels and location with the levels and location of said imaging agent from an otherwise identical location from an unaffected subject or with an unaffected area of said test subject, wherein a higher level or different location of said imaging agent in said test subject compared with the level or location of said imaging agent in said sample from an unaffected subject or from an unaffected area of said test subject, is an indication that said test subject has a cancer expressing Plectin-1 or a homolog or fragment thereof, thereby detecting cancer, diagnosing cancer, monitoring the progression of cancer, or monitoring treatment of a cancer, wherein said cancer cells express Plectin-1 or a homolog or fragment thereof.

2. The method of claim 1 , wherein said cancer is selected from the group consisting of head and neck cancer, liver cancer, pancreatic cancer, esophageal cancer, stomach cancer, lung cancer, breast cancer, ovarian cancer, uterine cancer, endometrial cancer, cervical cancer, prostate cancer, adrenal cancer, lymphoma, salivary gland cancer, bone cancer, brain cancer, cerebellar cancer, colon cancer, rectal cancer, colorectal cancer, oronasopharyngeal cancer, nasopharyngeal carcinoma (NPC), kidney cancer, bladder cancer, skin cancer, melanoma, basal cell carcinoma, hard palate carcinoma, squamous cell carcinoma of the tongue, meningioma, pleomorphic adenoma, astrocytoma, chondrosarcoma, cortical adenoma, hepatocellular carcinoma, pancreatic cancer, squamous cell carcinoma, and adenocarcinoma.

3. The method of claim 2 , wherein said cancer is pancreatic cancer.

4. The method of claim 3 , wherein said pancreatic cancer is selected from the group consisting of pancreatic ductal adenocarcinoma, pancreatic intraepithelial neoplasia, adenoma, adenoma with dysplasia, and carcinoma in situ.

5. The method of claim 1 , wherein said cancer is a metastatic cancer.

6. The method of claim 1 , wherein when said test subject is diagnosed with pancreatic cancer, said test subject is treated surgically to remove said cancer by administering a composition comprising a multimeric peptide ligand complex of the invention for distinguishing pancreatic cancer cells from non-cancer cells, imaging said pancreatic cancer cells with an imaging device and surgically removing said pancreatic cancer cells from said test subject following detecting the location of said pancreatic cancer cells.

7. The method of claim 1 , wherein said imaging agent is 111 In.

8. The method of claim 1 , wherein said imaging agent is selected from the group consisting of a radionuclide, a radiological contrast agent, a paramagnetic ion, a metal, a biological tag, a fluorescent label, a chemiluminescent label, an ultrasound contrast agent and a photoactive agent.

9. The method of claim 1 , wherein said Plectin-1 or a homolog or fragment thereof is a cell surface Plectin-1 or a homolog or fragment thereof.

10. The method of claim 1 , wherein said tetrameric peptide ligand complex comprising an imaging agent has the structure: