• Major histocompatibility complex (MHC)

    A set of proteins on the surface of certain immune cells that influence the interaction of normal cells with immune cells. Antigen-presenting cells present digested antigens to T-cells through the MHC on their surface, which allows the T-cells to “see” the antigen and recognize it as foreign. The connection between the MHC and the receptor on the T-cell is the first signal (Signal 1) necessary to activate the T-cell to respond to a tumor and destroy it. [Patient Resource LLC]

  • Memory cells

    T-cells and B-cells from a specific immune reaction that continue to circulate in the body even after the infection is resolved. They “remember” specific antigens and can multiple rapidly upon subsequent exposure, creating an immediate immune response already trained to eliminate the threat. [Patient Resource LLC]

  • Metabolomics

    The large-scale study of small molecules, commonly known as metabolites, within cells, biofluids, tissues or organisms. Collectively, these small molecules and their interactions within a biological system are known as the metabolome. [From]

  • Metastasis

    The spread of cancer cells from the place where they first formed to another part of the body. In metastasis, cancer cells break away from the original (primary) tumour, travel through the blood or lymph system, and form a new tumour in other organs or tissues of the body. The new, metastatic tumour is the same type of cancer as the primary tumour. For example, if breast cancer spreads to the lung, the cancer cells in the lung are breast cancer cells, not lung cancer cells. [NCI]

  • Microbiome

    The collection of all the microorganisms and viruses (microbiota) that live in a given environment, including the human body or part of the body, such as the digestive system. The human microbiome may play a role in a person’s health. Studying the human microbiome may help prevent and treat disease in the future. [NCI]

  • Micrometastases

    The spread of cancer cells in groups so small that they can only be seen under a microscope. [ACS]

  • Mitochondria

    Small structures in a cell that are found in the cytoplasm (fluid that surrounds the cell nucleus). Mitochondria make most of the energy for the cell and have their own genetic material that is different from the genetic material found in the nucleus. Many diseases are caused by mutations (changes) in the DNA of mitochondria. Mitochondria are cell organelles. [NCI]

  • Model systems

    Systems used to test hypotheses on what interventions may work with humans. In vitro (outside of a living being) systems are cultured cells, generally from humans. The more recent type of in vitro system is 3D cell cultures created from human cells, which are spherical in shape and thought to more closely resemble human tumours. In vivo models (models in living beings) are of two main types:

    • patient-derived or zenograft models, where human cancerous cells or tissues are implanted into a mouse or other animal to simulate human tumour biology
    • transgenic/genetically engineered models, where new or altered genes are inserted into the genome of a mouse or other animal by genetic engineering techniques, thereby making them more susceptible to cancer

    Although mouse models are the mainstay of cancer research, zebrafish, a member of the minnow family, have become a popular model organism in cancer research and Canada has several leading experts. Zebrafish grow quickly, are nearly transparent allowing their internal structures to be easily examined, have had their genome fully sequenced, and share a similar genetic structure to humans. [From]

  • Monoclonal antibodies (mAbs)

    Antibodies made in a laboratory that are designed to target specific parts of cancer cells, which may include certain proteins or molecules on the surface of the cancer cells; they are meant to stimulate an immune response in the same way as naturally produced antibodies do. [Patient Resource LLC]

  • mRNA

    Short for messenger RNA. A type of RNA found in cells. mRNA molecules carry the genetic information needed to make proteins. They carry the information from the DNA in the nucleus of the cell to the cytoplasm where the proteins are made. [NCI]

  • Mutation

    A change in the DNA of a cell. Most mutations do not cause cancer, and a few may even be helpful. But all types of cancer are thought to be due to mutations that damage a cell’s DNA. Some cancer-related mutations can be inherited (passed on from a parent). This means that the person is born with the mutated DNA in all the body’s cells. But most mutations happen after the person is born. These are called somatic or acquired mutations. This type of mutation happens in one cell at a time, and only affects cells that arise from the single mutated cell. [ACS]