1 - Cancer + Cellular Regulation Flashcards
What is a neoplasm?
a neoplasm (aka a tumor) is an abnormal mass of cells which grow and divide w/o response to normal regulatory controls
Define proliferation
normal cells divide to develop normal tissues to replace lost / damaged normal tissues
Define differentiation
cells acquire functions that are different from those of their original cell from which they came; cell maturation
Describe contact inhibition
Normal cells respect the boundaries of surrounding cells and won’t grow into their space; growth is inhibited through physical contact w surrounding membranes
What is a biopsy? Identify the 3 types of biopsies.
definitive means of diagnosing cancer; piece of tissue is surgically removed from the suspect area for histological examination.
this examination helps determine whether the tissue is benign or malignant, the anatomical tissue from which the tumor arises, and the degree of cellular differentiation
3 TYPES: needle, incisional, excisional
What is chemotherapy?
use of chemicals as a systemic therapy for cancer
What is radiation therapy?
local treatment modality for cancer
use of radiation in a controlled way to prevent the continued growth of highly mitotic cancer cells
Define cachexia
weakness + wasting of the body due to cancer
What is pancytopenia?
marked decrease in the # of RBCs, WBCs, and platelets
What is neutropenia?
What is the normal range of neutrophils?
neutrophil count of less than 1 to 1.5 x 10^9 / L (normal range is 2.2 – 7.7)
What is thrombocytopenia?
reduction of platelets below 150 x 10^9 / L
Define myelosuppression (bone marrow suppression).
decrease in bone marrow activity resulting in the reduced production of blood cells
common side effect of chemotherapy
What is a carcinogen?
cancer-causing agents capable of producing cellular alterations; anything that promotes carcinogenesis
What is stomatitis?
inflammation of the mouth + lips; inflammed, sore mouth
What is mucositis?
painful inflammation and ulceration of the mucous membranes lining the digestive tract; usually as an adverse effect of chemotherapy + radiotherapy
What is alopecia?
partial or complete (reversible) loss of hair resulting from normal aging, endocrine disorders, drug rxns, anticancer medications, or skin diseases
What are CSFs (colony stimulating factors)?
glycoproteins that stimulate the production, maturation, regulation, and activation of cells of the hematological system
also stimulate the production, maturation, and release of blood cells from the bone marrow + their functional ability
What is the function of proto-oncogenes?
Promote growth + regulate normal cellular processes; start the cell cycle
What is the function of tumor suppressor genes?
Supresses growth + ends the cell cycle; also sense if a mutation is taking place
What is an oncogene?
An oncogene is a mutated cell growth regulator that promotes tumor growth; a cancer causing gene
What is cellular regulation?
All functions carried out w/in a cell to maintain homeostasis, including intracellular responses to extracellular signals.
What is cancer?
The unregulated and uncontrolled growth of cells.
What are the top 3 types of cancers that occur in males?
1) prostate
2) lung and bronchus
3) colorectal
What are the top 3 types of cancers that occur in females?
1) breast
2) lung and bronchus
3) colorectal
What are the 3 most common forms of cancer in childhood?
1) leukemia
2) brain tumors
3) lymphomas
Define + describe the current theory of cancer formation.
The current theory of cancer formation states that cancer occurs as a result of multiple + sequential mutations that impair a cell’s ability to control its cell cycle + replication
Identify the 4 characteristics of malignant cells.
1) proliferation w/o limits
2) evasion of apoptosis
3) acquisition of vasculature (angiogenesis)
4) ability to invade other tissues and metastasize
Define metastasis.
Metastasis occurs when tumor cells break free of a tissue and are circulated to distant tissues in the blood and / or lymph; results in secondary tumors
What is the most common site of metastasis? What is the second most common site?
The most common site of metastasis is the lungs because the pulmonary capillaries are often the first beds encountered by systemic tumor cells.
Second most common site is the liver.
Provide 2 examples of mutated tumour suppressor genes.
1) BRCA1 - genetic mutation; mutated to breast + ovarian cancer
2) P53 - most mutated gene in all of human cancer
What is carcinogenesis?
Process by which normal cells become transformed into malignant cells; initially involves mutations in DNA
What are the 5 types of DNA mutations that occur in carcinogenesis?
genetic (ex - BRCA1) chemical environmental (ex - UV) viral or immunological unidentified
Identify the 3 processes of cancer development.
Initiation
Promotion
Progression
What happens during initiation?
Normal cell gets altered / transformed by genetic mutations from multiple sources such as viruses, hormones, radiation, chemicals, genetic factors, or unknown factors.
This alteration leads to dysfunction in the cell’s differntiation and proliferation.
What happens during the promotion phase? Which hormones can impact promotion?
Cancer cell begins proliferating at tissue of origin.
Promotion can be enhanced by steroid homrones such as estrogen and testoseterone.
What happens during the progression phase?
Evidence of clinical disease is present, eventual evidence of regional spread and metastasis.
Which cancer is associated with the Epstein- Barr Virus?
Burkitt’s Lymphoma
Which cancer is associated with HIV?
Kaposi Sarcoma
Which cancer is associated with Hep B?
Hepatocelular carcinoma.
Hep B increased the risk of developing liver cancer by 300%.
Which cancer is associated with HPV?
Squamous Cell Carcinoma, especially in the cervix.
What is nutrient trapping?
Tumours rob the surrounding cells of nutrients
What are the 5 local signs of cancer found on assessment?
1) visible lesions
2) physical asymmetry
3) palpable masses
4) abnormal sounds
5) pain
what are the 5 systemic signs of cancer found on assessment?
1) anemia
2) bleeding
3) cachexia
4) fever
5) infections
How does anemia occur as a sign of cancer?
From blood loss, iron deficiency, or bone marrow suppression / invasion
How does bleeding occur as a symptom of cancer?
Bleeding occurs as a result of tumor necrosis and erosion of blood vessels, bone marrow suppression / invasion, or secondary to chemotherapy
How does cachexia occur as a symptom of cancer? How does cachexia affect the patient?
Cachexia occurs as a result of anorexia, increased catabolism (associated w release of cytokines), and nutrient trapping.
Cachexia almost behaves like a disease of its own. When you lose muscle mass you not only become weaker, but you lose the ability to tolerate the harsh side effects of cancer treatment. Pts w cachexia often feel both tired and nauseated, and increased nutrient intake cannot compensate for it.
Cachexia is associated with increased mortality rates of cancer pts.
What is the lifetime probability of cancer in Canada?
44%.
What do anemia, bleeding, and infections have in common?
These symptoms are signs that the cancer or cancer therapy has invaded or suppressed the bone marrow