Chapter 1 Notes from Chapter 1 of Principles of Cancer Biology by Lewis J Kleinsmith Read before Lecture 3 Cancer strikes older people more frequently than younger people and more cancer cases are being seen simply because people are living longer than they did in the past Page 2 Lung cancer a disease that accounts for roughly one of every three cancer deaths Colorectal breast and prostate cancers are also among the top five in terms of in the United States Page 3 total cancer fatalities Page 3 Pancreatic cancer not even in the top ten cancers in terms of overall frequencies is the fourth leading cause of cancer deaths in the U S because it is the one of the most difficult cancers to treat Page 3 Although lung cancer is currently the number one cancer killer in the U S it s not always been the case lung cancer was one of the rarest forms of cancer 100 years ago Page 3 In Japan where the tradition diet is quite unlike that in the U S stomach cancer rates are almost ten times higher and stomach cancer kills almost as many Japanese as does lung cancer Page 3 Dysplasia An abnormal growth process that produces tissue in which proper cell and tissue organization has been disrupted It can range from mild moderate or severe Page 5 Dysplasia can also become more severe eventually progressing to a more dangerous form of tissue Neoplasia Page 5 Neoplasia Is an abnormal type of tissue growth in which cells proliferate in an uncontrolled relatively autonomous fashion leading to an continual increase in the number of growing cells Page 5 This loss of cell creates a proliferating mass of abnormal cells called a neoplasm or tumor Page 5 Cell Differentiation The process by which cells acquire the specialization properties that distinguish different types of cells from one another In tumors this finely balanced arrangement is disrupted and some cell divisions give rise to two cells that both continue to divide thereby feeding a progressive increase in the number of cells Page 5 Benign tumors Grow in a confined local area Page 5 Malignant tumors Can invade surrounding tissues enter the bloodstream and spread to distant parts of the body by metastasis Page 5 Cancer refers to any malignant tumor Page 5 Basal Cells Divide it gives rise to two cells with different fates One cell stays in the basal layer and retains the capacity to divide and undergoes differentiation as it leaves the basal layer and moves toward the outer skin surface Page 5 The fully differentiated thin flat cells that form the outer layer of the skin looks almost like scales and are referred to as squamous cells Page 5 Well differentiated cells meaning that the cells bear a close structural and functional resemblance to the normal cells of the tissue in which the tumor has arisen Page 6 Malignant tumors grow more rapidly and their state of differentiation is variable Page 6 Carcinomas are cancers that arise from the epithelial cells that form covering layers over external and internal body surfaces Page 6 Sarcomas are cancers that originate in supporting tissues such as bone cartilage blood vessels fat fibrous tissue and muscle They are the rarest form of cancer About 1 of the total cancer diagnoses Page 6 Lymphomas Refers to tumors of white blood cells that grow mainly as solid masses of tissue Page 6 blood stream Page 6 Leukemia s are cancers in which malignant blood cells proliferate mainly in the Differences are even exhibited by cancers of the same kind Page 8 Cancer cells produce substances that interfere with the function of the immune system thereby making people more susceptible to potentially lethal infections The drugs or radiation treatments that are commonly used to treat cancer patients also tend to inhibit immune function creating the risk of infections that can be lethal Page 9 Presence of cancer cells in the body sometimes triggers cachexia a life threatening condition characterized by extensive weight loss weakness and mal nutrition Page 9 Five year survival rate which is defined as the percentage of cancer patients who are still alive five years after initial diagnosis Page 9 Tendency for survival when no improvement has actually occurred is called lead time bias Page 10 Cancers generally have a higher mitotic index than benign tumors and faster growing cancers will have a higher index that slower growing cancers Page 11 Anaplastic Which means that they are so poorly differentiated and abnormal in appearance and organization that they bear little resemblance to the cells of the tissue in which the tumor arose Page 11 Tumors must trigger the development of blood vessels that supply nutrients and oxygen to the tumor and remove waste products Without this step tumors cannot grow beyond a tiny size After tumors have triggered the formation of a blood supply cancer cells invade through surrounding tissues Page 12 Oncogenes Are defined as genes whose presence can lead to cancer They arise by mutation from normal genes that code for proteins involved in stimulating cell proliferation and survival Page 12 Oncogenes contribute to the uncontrolled proliferation and survival of cancer cells Page 12 Tumor Suppressor Genes Are normal genes whose deletion or loss of function can likewise lead to cancer Page 13 Nucleotides building blocks of DNA Page 13 Nitrogen containing base Adenine A Guanine G Cytosine C and Thymine T Page 13 Complementary Base pairing A bonds with T and G bonds with C Gene A gene is any nucleotide sequence in DNA that codes for a functional product Transcription DNA is read by DNA Polymerase and transcribed into mRNA Translation mRNA is translated by ribosomes into a protein
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