Compositions and methods for identifying and targeting cancer cells of alimentary canal origin

An in vitro method of screening an individual for metastatic colorectal cancer cells or primary and/or metastatic stomach or esophageal cancer cells comprising the steps of examining a sample of extraintestinal tissue and/or body fluids from an individual to determine whether SI gene transcription or translation product is present in said sample wherein the presence of SI gene transcription or translation product in said sample indicates that the individual may have metastatic colorectal cancer cells or primary and/or metastatic stomach or esophageal cancer cells in said sample.

An in vitro method of confirming that a tumor cell removed from a patient suspected of having colorectal, stomach or esophageal cancer cells is a colorectal, stomach or esophageal tumor cell comprising the step of determining whether a tumor cell expresses SI wherein expression of SI indicates that the tumor cell is a stomach or esophageal tumor cell.

A method of diagnosing an individual who has stomach cancer comprising the steps of examining a sample of stomach tissue to detect the presence of SI transcript or translation product wherein the presence of SI transcript or translation product in a stomach sample indicates stomach cancer.

A method of diagnosing an individual who has esophageal cancer comprising the steps of examining a sample of esophagus tissue to detect the presence of SI transcript or translation product wherein the presence of SI transcript or translation product in an esophageal sample indicates esophageal cancer.

A method of treating an individual suspected of suffering from metastasized colorectal cancer, or primary and/or stomach or espophageal cancer comprising the steps of administering to said individual a therapeutically effective amount of a composition comprising:

• i) an SI ligand;
• and,
• ii) an active agent.

A method of radioimaging metastasized colorectal cancer cells comprising the steps of administering to an individual a composition comprising an SI ligand linked to a detectable agent.