The disclosed method of treating a malignant solid tumor in a subject includes the steps of administering to the subject an immunomodulatory dose of a radioactive phospholipid metal chelate compound that is differentially retained within malignant solid tumor tissue, and performing in situ tumor vaccination in the subject by introducing into at least one of the malignant solid tumors one or more agents capable of stimulating specific immune cells within the tumor microenvironment, or by performing another method of in situ tumor vaccination. In a non-limiting example, the radioactive phospholipid metal chelate compound has the formula:

##STR00001## wherein R.sub.1 comprises a chelating agent that is chelated to a metal atom, wherein the metal atom is an alpha, beta or Auger emitting metal isotope with a half life of greater than 6 hours and less than 30 days. In one such embodiment, a is 1, n is 18, m is 0, b is 1, and R.sub.2 is N.sup.+(CH.sub.3).sub.3.

Disclosed herein is a fractionated dosing regimen of 131I-labeled 18-(p-iodo-phenyl)octadecyl phosphocholine for the treatment of cancer. The dosing regimen may include a single dosing cycle or multiple dosing cycles. The radiation therapy as described herein may be administered pursuant to a first dosing cycle and a second dosing cycle, with a delay between the two cycles necessitated by a medical reason of the subject.

Disclosed herein are methods of treating a tumor or cancer in a subject whose tumor or cancer cells express low levels of asparagine synthetase (ASNS), and compounds and compositions useful in such treatment. Also disclosed herein are methods of evaluating whether to administer a compound that inhibits glutathione production or a glutaminase inhibitor to a subject with a tumor or cancer.

Disclosed herein are methods of treating a tumor or cancer in a subject whose tumor or cancer cells express low levels of asparagine synthetase (ASNS), and compounds and compositions useful in such treatment. Also disclosed herein are methods of evaluating whether to administer a compound that inhibits glutathione production or a glutaminase inhibitor to a subject with a tumor or cancer.

Dual-modality contrast agents are disclosed herein, having the general formula:

##STR00001## R.sub.1 includes a chelating moiety that is chelated to a Mn.sup.2+ isotope. The disclosed contrast agents differentially target a wide range of malignant tumor tissues, and can be simultaneously used as contrast agents for both magnetic resonance imaging (MRI) and positron emission topography (PET) imaging. Accordingly, the disclosed contrast agent can be used in diagnosing and monitoring solid tumor cancers.

Disclosed are methods for diagnosing pancreatic cancer, including measuring the expression level of ASCT1 and/or ASCT2 and/or XPR1. Also disclosed is a RBD ligand coupled to at least one contrast agent, that may be used as a probe for medical imaging.

A method of treating a malignant solid tumor in a subject is disclosed herein. The method includes the steps of administering to the subject an immunomodulatory dose of a radiohalogenated compound that is differentially taken up by and retained within malignant solid tumor tissue, and performing in situ tumor vaccination in the subject by intratumorally injecting into (or treating via a separate method) at least one of the malignant solid tumors a composition that includes one or more agents capable of stimulating specific immune cells within the tumor microenvironment. In certain exemplary embodiments, the radiohalogenated compound has the formula: ##STR00001##
wherein R.sub.1 is a radioactive halogen isotope, n is 18 and R.sub.2 is N.sup.+(CH.sub.3).sub.3.

Methods and compositions utilizing ether and alkyl phospholipid ether analog compounds for treating cancer and imaging, monitoring, and detecting cancer stem cells in humans.

Presented herein are methods and compositions for non-invasive imaging of TAMs with discoidal high-density lipoproteins to assess prognosis and therapy outcome. TAMs are increasingly investigated in cancer immunology, and are considered a promising target for better and tailored treatment of malignant growths. Although TAMs also have high diagnostic and prognostic value, TAM imaging still remains largely unexplored. Imaging agents/methods provided herein are of value for non-invasive in vivo evaluation of TAM burden, not only in preclinical but also in clinical settings.

The disclosed method of treating a malignant solid tumor in a subject includes the steps of administering to the subject an immunomodulatory dose of a radioactive phospholipid ether metal chelate, a radiohalogenated phospholipid ether, or other targeted radiotherapy (TRT) agent that is differentially retained within malignant solid tumor tissue, and either (a) performing in situ tumor vaccination in the subject by introducing into at least one of the malignant solid tumors one or more agents capable of stimulating specific immune cells within the tumor microenvironment, or (b) performing immunotherapy in the subject by systemically administering to the subject an immunostimulatory agent, such as an immune checkpoint inhibitor. In a non-limiting example, the radioactive phospholipid ether metal chelate or radiohalogenated phospholipid ether has the formula:

##STR00001##

wherein R.sub.1 comprises a chelating agent that is chelated to a metal atom, wherein the metal atom is an alpha, beta or Auger emitting metal isotope with a half-life of greater than 6 hours and less than 30 days, or wherein R.sub.1 comprises a radioactive halogen isotope. In one such embodiment, a is 1, n is 18, m is 0, b is 1, and R.sub.2 is N.sup.+(CH.sub.3).sub.3.