What Can Immunology Tells Us About Breast Cancer?

Immunology Terms Immunology: “Broad branch of biomedical science that covers the study of all aspects of the immune system in all organisms.”1 Antigens and antibodies White blood cells (leukocytes) and other immune cells Tissues and organs (lymph nodes, spleen) Lymph nodes: Small tissues throughout the body containing immune cells. Fluid (hence antigens and other materials) from tissues “drain” into lymph nodes, which can trigger immune responses. Slide Credits: Defintion of immunology from “Immunology.” Wikipedia, accessed 8/7/2009 Picture of lymph nodes on left from: http://myhealth.ucsd.edu/library/healthguide/en-us/images/media/medical/hw/h9991282_001.jpg http://www.acm.uiuc.edu/sigbio/project/updated-lymphatic/lymph_node.gif Teacher Notes: Depending on how much detail you want to cover re: the lymphatic system, you may want to say more about lymph nodes than what I have here. An in-depth introduction to the lymphatic system is not necessary for students to understand the activity that they will do.

Breast Cancer and Lymph Nodes Lymph nodes around the breasts and armpit are removed for staging breast cancer Lymph nodes checked for tumor cells only (node-positive vs. node-negative) Research questions: Do the proportions of the different kinds of immune cells in lymph nodes change in breast cancer patients? What about the cells’ spatial distributions (where they are in the tissue)? Can this information help us predict how well patients will do (prognosis) and how we treat them? Information from various sources, including: http://www.mayoclinic.com/health/breast-cancer-staging/BR00022 Kohrt HE, Nouri N, Nowels K, Johnson D, Holmes S, Lee, PP. 2005. Profile of immune cells in axillary lymph nodes predicts disease-free survival in breast cancer. PLoS Med; 2(9):e284.

Identifying Cells in Tissues Goal: Make specific kinds of cells visible under the microscope, and count them. Every cell type has specific markers (antigens!!!) on the surface! How can we apply the ideas behind ELISA and Western blots here? Image modified from: http://commons.wikimedia.org/wiki/File:Immunohistochemistry.jpg Teacher Notes: You may want to have students do a think-pair-share with the question “How can we apply the ideas behind ELISA and Western blots here?” Again, it is assumed that students have been taught the science behind ELISA and Western blots and/or have performed them. The Cell Identification Activity that follows this PowerPoint in the lesson sequence CAN be done with no references to ELISA and Western blots, however. Answer to question: Identify antigens specific to each cell type of interest. Identify primary antibody/secondary antibody combination for each antigen that will not interact with other primary antibody/secondary antibody combinations. For example, for antigens X and Y - one possible pairing set: Antigen X: Primary: Mouse Anti-X, Secondary: Anti-Mouse/enzyme complex Antigen Y: Primary: Goat Anti-Y, Secondary: Anti-Goat/ enzyme complex Use different substrates/ chromogens for each antigen to stain for different colors.

Immunohistochemistry Immunohistochemistry (IHC) takes advantage of concepts behind immunology (antigens/antibodies) and chemistry to stain and study tissues (histology) How is this better than ELISA/ Western blots (or is it)? Teacher Notes: The last question is for students to think about; you do not necessarily have to have them answer this now. This will be addressed later after they have done the Cell Identification Activity.

Lymph Node IHC Staining Teacher Notes: The panels on the right are density maps showing where different kinds of cells (tumors, dendritic cells, T-cells, and other cells, are located after all cells were identified using an image classification program. Tumor cells: Red Dendritic cells (DCs in diagram): Dark brown T-cells: Bright blue Other cells: Light blue Note that the light blue and bright blue are difficult to differentiate with the naked eye in this picture -- use the density maps on the right as a guide.