Genetic Disorders Presentation and Cancer Genetics Overview

Genetic Disorders Overview

• Presentation topics include Sickle Cell Anemia and PKU (Phenylketonuria).

• Both conditions are considered autosomal recessive disorders. Sickle Cell Anemia leads to abnormal hemoglobin, causing red blood cells to become rigid and sickle-shaped, which can block blood flow and cause pain. PKU is a metabolic disorder caused by a deficiency in the enzyme phenylalanine hydroxylase, leading to an accumulation of phenylalanine that can cause severe developmental issues if not managed through a strict diet.

Course Structure and Content

• The course will cover cancer genetics today and discuss human genetic variants in subsequent classes.

• Important concepts include determining if genetic variants are benign, pathogenic, or somewhere in between, using databases and assessment tools to classify these variants based on their clinical significance.

Cancer Genetics

• Today's discussion revolves around:

  • Oncogenes: Genes that have the potential to cause cancer when activated or mutated. They generally promote cell growth and division. Mutations may lead to their hyperactivation, resulting in excessive proliferation.

  • Tumor Suppressor Genes: Genes that normally prevent uncontrolled cell growth; mutations can lead to cancer by disabling these regulatory controls. Examples include the p53 gene.

• Students will analyze CDC data on cancer incidence and prevalence, comparing data from 2022 and 2023 to identify trends and variations in specific cancers over time.

Class Participation and Materials

• Presenters must upload their PowerPoint presentations by 1:30 PM on the day of their talk for assessment and feedback.

• A paper related to the presentation topic must be sent to the instructor at least two weeks prior for approval, ensuring that all materials reflect the most current research and standards in the field.

• Each presentation should follow the rubric focusing on background, methods, and results from original research articles to provide depth and scholarly support for the topic discussed.

Discussion Boards

• Students are required to participate in discussion boards: Read assigned papers and post questions 2 days before peer presentations, facilitating a deeper understanding of the material and stimulating discussion.

• Accessing discussion boards requires a post; this restriction is to be corrected by the instructor to ensure equitable access to participation for all students.

Data Analysis

• Activity where students analyze cancer mortality data:

  • Discovering trends in cancers compared to previous years (e.g., considering COVID's impact, unintentional injuries, chronic liver disease).

  • Discussion of lifestyle factors affecting cancer statistics (such as obesity, smoking, dietary habits, and environmental factors).

Cancer Incidence and Mortality Data

• Prostate Cancer: Increased incidence attributed to better screening methods (PSA tests). Screening practices have evolved, enabling earlier detection and intervention.

• Breast Cancer: Ongoing increase in incidence; linked to lifestyle factors and improved educational efforts regarding screenings, highlighting the importance of awareness and preventative measures.

• Lung Cancer: Noticeable decrease in incidence among males, potentially due to improved smoking regulations and awareness campaigns, showcasing the impact of public health policies.

Survival Rates

• Lifetime probability of developing cancer exceeds 1 in 3, indicating a significant public health challenge.

• Five-year relative survival rates for cancer have improved significantly since 1975 due to advancements in early detection, treatment options, and supportive care.

Causes of Cancer

• Mutagens: Chemicals that cause mutations leading to cancer (e.g., cigarette smoke, certain industrial chemicals).

• Radiation: UV radiation and ionizing radiation can cause DNA damage, leading to cancer, notably skin cancer and leukemia.

• Infectious Agents: Certain viruses (such as HPV) can increase cancer risk; awareness and vaccination are key preventative strategies.

• Genetic factors: Heritability can contribute to inherited cancer risks, with specific genes being associated with heightened risk for certain types of cancer, like BRCA mutations for breast and ovarian cancers.

Tumor Characteristics

• Distinction between benign (non-invasive, growing slowly, typically not life-threatening) and malignant tumors (invasive and spreading, with potential to metastasize). Understanding these differences is crucial for diagnosis and treatment planning.

Mechanisms of Oncogenesis

• Oncogenes promote excessive cell proliferation; tumor suppressor genes prevent it. The balance between these mechanisms is critical for normal cell function.

• Mutations in these genes can lead to uncontrolled growth or failure to initiate programmed cell death (apoptosis), contributing to cancer development.

Understanding Mutations

• Dominant mutations in oncogenes can lead to cancer with just one mutated allele, as the presence of the mutant gene can override normal function.

• Recessive mutations in tumor suppressor genes generally require loss of both alleles to express cancer phenotypes.

• Example gene: BRCA1/BRCA2 - known to increase breast cancer risk, requiring both alleles to be mutated for a phenotypic effect. These genes are critical components in the repair of damaged DNA.

Assignments and Collaboration

• Students will collaborate on a spreadsheet to present research findings on genes associated with cancer, addressing their roles, related cancers, inheritance types, and source citations. This collaborative effort encourages peer learning and resource sharing, enhancing overall understanding of cancer genetics.