Biology & Immunology Flashcards
4 Bases of DNA
Adenine
Thymine
Guanine
Cytosine
Transcription
Process for DNA to RNA via RNA polymerase
Translation
Process from mRNA to strand of amino acids which forms a protein
Essential Amino Acids
Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine Arginine* Cysteine* Glutamine* Pyrrolysine* Proline* Selenocysteine* Serine* Tyrosine*
Which cells don’t proliferate after birth?
Nerve cells
Muscle cells
Cardiac cells
Which cells are capable of self-renewal?
Stem cells
2 Types of Growth Factors
Stimulate cell division
Inhibit cell division
Cell Cycle Phases
G0 G1 S G2 M
Define G0 Phase
A resting phase where the cell has left the cycle & has stopped dividing
Define G1 Phase
Cells increase in size
What is the G1 checkpoint?
Control mechanism ensures that everything is ready for DNA synthesis
Define S Phase
DNA replication occurs during this phase
Define G2 Phase
Gap between DNA synthesis & mitosis
Cell continues to grow
What is the G2 checkpoint?
Control mechanism ensures that everything is ready to enter the M phase & divide
Define M
Cell growth stops at this stage & cellular energy is focused on the orderly division into two daughter cells
What is the metaphase checkpoint?
Ensures that the cell is ready to complete cell division
2 Categories of Cancer Genes
Dominant: proto-oncoggenes
Recessive: tumor suppressor
Define Gain of Function Mutations
Altered or unregulated activity of a “photo-oncogene” leads to tumorigenesis
Define Loss of Function Mutations
Loss of activity of tumor suppressors results in unregulated pathways and tumorigenesis
“Hallmarks of Cancer”
Self-sufficiency in growth signals Insensitivity to anti-growth signals Evading apoptosis Limitless reproductive potential Capacity to invade other tissues Sustained angiogenesis Tissue invasion & metastases Genomic instability
How do cancer cells invade our bodies?
Resisting apoptosis CSCs forming resistant phenotypes Epithelial-mesenchymal transitions Interactions with microenvironment Invadopodia & aquaporins Genetic alterations
Invadopodia
Actin rich membrane protrusion formed by invasive cancer cells (protrude through basement membranes)
Cancer Stages
Stage 0: mucosa level Stage 1: through the submucosa Stage 2: through the muscle layers Stage 3: through the serosa Stage 4: through serosa and spread to other organs
of Mutations with Gain of Function
Single mutation event
of Mutations with Loss of Function
2 mutation events
How do proto-oncogenes normally function?
Associated with cell growth, cell division, & cell differention
What can proto-oncogenes be?
Cell surface receptors
Adapter molecules
Enzymes: kinases/phosphatases
Type of Cells in Carcinomas
Epithelial cells
Types of Cells in Sarcomas
Connective tissue cells
Types of Cells in Lymphomas & Leukemias
Blood
Types of Cells in Germ Cell Tumors
Testicle & ovary
Types of Cells in Blastomas
Immature cells
Embryonic tissue
Methods of Identification of Cancer Critical Genes
Assay for oncogenic effects
Study of rare syndromes-tumor suppressors
Candidate genes
Genomics
How does Metastasis Occur?
Transformed cell Invasion of basement membrane Passage through extracellular matrix Intravasation Interaction with lymphoid cells Tumor embolus Adhesion to basement membrane Extravasation Metastatic deposit Angiogenesis Growth
How does cancer spread throughout the body?
Blood stream
Lymphatic fluid system
Seed into peritoneal, pericardial, or pleural spaces
Most Common Site of Breast Metastasis
Bone
Most Common Site of Colorectal Metastasis
Liver
Most Common Site of Prostate Metastasis
Bone
Why are some cancers more aggressive than others?
Biology: ploidy
Aneuploidy
Grading of Tumors
1: Well differentiated
2: Moderately differentiated
3: Poorly differentiated
4: Undifferentiated anaplastic
Characteristics & Growth Rate of Well Differentiated Tumors
Characteristics: looks like tissue of origin
Growth: slow, close to normal cell divisions
Characteristics & Growth Rate of Moderately Differentiated Tumors
Characteristics: many features like tissue of origin; less organized
Growth: faster; occasional mitosis
Characteristics & Growth Rate of Well Differentiated Tumors
Characteristics: few features of tissue of origin; little organization
Growth: more mitosis
Characteristics & Growth Rate of Undifferentiated Anaplastic Tumors
Characteristics: no features to help distinguish origin
Growth: Mitoses throughout tissue
Old Cancer Model
Tumor cells can form new tumors & are tumorigenic
Unregulated growth due to expression of genes that promote cell proliferation, silencing of growth inhibitory genes, & blunting of cell death
Cancer is proliferative disease
New Cancer Model
Tumors arise from cancer stem cells
Unregulated growth due to a disruption in regulatory mechanisms in stem cell renewal
Cancer is a stem cell disorder
Stem cells persist in tumors which causes relapses & metastasis
What do traditional cancer therapies treat?
Kill rapidly dividing tumor cells but spare the stem cells that give rise to a new tumor
What should halt a tumor’s growth & lead to it’s disappearance?
Killing cancer stem cells
What are cancer stem cells?
Cells that have properties of normal stem cells such as:
1) ability to self-renew
2) ability to differentiate into multiple cel types
3) form distinct population in tumors that likely causes disease relapse & metastasis
What cancers are more common with hereditary breast/ovarian cancer syndrome?
Breast Ovarian Male breast Prostate Pancreatic
What cancers are more common with Lynch (HNPCC) syndrome?
Colon Gastric Endometrial Ovarian Small bowel Pancreas Brain Ureters Kidney
What cancers are more common with familial adenomatous polyposis syndrome?
Colon Stomach Thyroid Brain Liver Adrenal gland
Less Common Hereditary Cancer Syndromes
Li-Fraumeni Syndrome Cowden Syndrome Peutz-Jeghers Syndrome Xeroderma pigmentosa syndrome Von Hippel-Lindau Syndrome Multiple endocrine neoplasia-1 syndrome
Common Cancers with Li-Fraumeni Syndrome
Breast Bone LEukemia Brain Soft tissue sarcomas
Common Cancers with Cowden Syndrome
Breast Uterine Thyroid Ovarian Colon
Common Cancers with Peutz-Jeghers Syndrome
Colon Small bowel Breast Ovarian Pancreatic
Common Cancers with Xeroderma Pigmentosa Syndrome
Basal cell
Squamous cell
Melanoma
Common Cancers with Von Hippel-Lindau Syndrome
Brain Retina Kidney Pancreas Adrenal gland
Common Cancers with Multiple Endocrine Neoplasia-1 Syndrome
Pancreas
Pituitary
Parathyroid
Thyroid