Cancer Flashcards
What are cancer cells?
Dysfunctional cells that do not respond to extracellular/intracellular signals that control cellular growth and death
Which process do cancer cells evade?
Apoptosis
What occurs during the later phase of cancer?
Cells traverse through typical tissue boundaries and metastasize to new sites.
Which two classes of enzymes are responsible for intercellular signaling?
Cyclins and protein kinases
Which molecular cascade results in the promotion of transcription factors?
RAF-MERK-Erk cascade
Which types of genes encode for growth factor receptors?
Proto-oncogenes
Which types of genes become superactive within cancer cells?
Due to direct mutations of various genes that control cell proliferation. Growth promoting genes (protoncogenes) become super-active and produce cells that are strongly stimulated by growth receptors.
Which of the main type of genes are inactivated within cancer cells?
Tumour-suppressor genes
Which common tumor suppressor gene is inactivated?
p53
Why does an acquired mutation results in cancerous changes?
Acquired mutation can result in a growth advantage, that increased cellular proliferation and mitotic division compared to a normal cell- offspring outperforms non-cancerous counterparts in the competition for resources
The second mutation May provide the cancer cell with a reproductive advantage-intensifies competitive advantage.
Omitted checkpoints and suppressed repair genes contribute to the rate of damage accumulation
What are benign tumours?
Tumors are confined within the normal boundaries of tissues
What is a malignant tumour?
Tumour gains the ability to break through the specific tissue boundary and invasively adjoin to neighboring tissues.
Which types of enzymes are secreted by malignant cancer cells?
Proteases, enabling the degradation of the extracellular matrix at a tissue boundary
Proteases form a pathway for cancer cells to traverse (break down cell junctions and adhesive proteins)
What is metastasis?
Cancerous cells enter circulation or the lymphatic system, traveling to a new location of the body, beginning to divide and establish the foundation of new secondary tumour formation.
N.B: Cancer cells must have the ability to penetrate normal barriers of the body to enter and leave the blood/lymph vessels
What is cancer?
Cance is unchecked cell growth directed by genic mutations that cause cancer by accelerating cell division rates or inhibiting normal controls on the system (cell cycle arrest or apoptosis)
Mass of cancer cells can develop into a tumour
Malignancy occurs when cancer cells become invasive and invade adjacent tissues
Secondary tumours form during metastasis
Which types of drugs can be used to treat cancer?
Chemotherapy drugs: Counteract by blocking the action of growth signaling proteins
What is the mechanism of Herceptin?
Blocks over-active receptor tyrosinase kinases (RTKs)
What is the mechanism of Gleevec?
Blocks a mutant signaling kinase
What are the two main types of tumours?
Benign
Malignant
What are polyps?
Occur due to unregulated growth of healthy unmutated cells (Non-neoplastic tumours)
What is a neoplasm?
Refers to the formation of a mass due to abnormal cell or tissue growth
Autonomous (independent of stimuli), growth of tissue which has escaped the normal constraints of cell proliferation
What are the characteristic features of benign neoplasms?
Typically moveable and are not fixed
What is a hamartoma?
Localized benign overgrowths of multiple mature cell types.
Composed of abnormal mixture of cells in a disorganized manner typically found at the tissue site
Express architectural but no cytological abnormalities
Grows at the same rate of neighboring tissue
What is heterotopia?
The presence of a particular tissue type at a non-physiological site co-existing with another anatomically correct tissue type
What is an adenoma?
Benign glandular tumor
What is the term used to describe a malignant glandular tumor?
Adenocarcinoma
What is a chondroma?
Benign cartilage tumor
What is melanoma?
Malignant skin cancer
What is teratoma?
A germ tumour, containing tissue derived from three major types; forming 3 germ cell layers.
Teratomas contain mature tissue (benign), immature teratomas are malignant.
Multiple tissues: Hair, teeth, muscle or bone
What is invasion of malignant tumors?
Direct invasive expansion into adjacent connective tissue and other structures (blood vessels).
Increase cell proliferation of transformed cells in addition to the progressive increase in tumour size eventually leads to breaching the tissue boundaries, resulting in tumour extension
What distinguishes dysplasia/carcinoma in situ from cancer?
Dysplasia = non invasive
What is metastasis?
Development of secondary malignant growths at a distance from the primary site of cancer.
Separation from the primary tumour, followed by the invasion through tissues around the initial lesion and penetration of their basement membranes (protease enzyme activity), leads to entry into the circulatory system
Cancer cells spread via blood/lymph vessels (hematogenous spread)
What term is used to describe cancer spread via circulation and lymph vessels?
Haematogenous spread
What are the characteristic cytological features of tumor cells?
Larger nuclei
Therefore larger nuclear-cytoplasmic ratio
Loss of distinctive features (variation in nuclear size & shape)
Why do abnormal mitoses occur?
Aberrant centrosome amplification results in multipolar spindle contributing to aneuploidy
Mark unclear pleomorphism
What score parameter is used to evaluate qualitatively how much cancer from biopsy resembles that of a healthy tissue?
Gleason score
What is a direct extension?
Concerns primary tumour growth into adjacent structures & tissues
The direct extension is associated with a stromal response to the tumor
Includes fibroblastic proliferation (desmoplastic response)
Vascular proliferation and an immune response
What is another term for vascular proliferation?
Angiogenesis
What is hematogenous?
Metastasis and movement of cancerous growths through blood vessels (sarcomas) and lymphatics (carcinomas)
Vessels typically invaded are the venules & capillaries considering the respective walls are thin, thereby extravasation and intravasation are easier.
How is the pattern of the spread of cancer cells dictated within the lymphatic system to lymph nodes?
Dictated by normal lymphatic drainage of associated organs.
How do epithelial cancers metastasise first?
Via the lymphatic system, through this system tumor cells penetrate the basement membrane of the epithelium through this mechanism they arise carried partly by the hydrostatic pressure
What is transcoelomic?
Across the peritoneal cavity
Metastasis refers to the dissemination of malignant tumors throughout the surfaces and organs of the abdominal and pelvic cavity covered by the peritoneum (intra-abdominal cancers) and pleural cavities
What is perineural cancer?
Spread of cancer through nerves
What is the TNM system?
Tumour, Nodes, metastases
What is T is the TNM system?
T= Tumour size of extent of local invasion
What is N for the TNM system?
N= Nodes, number of lymph nodes involved
What is M for the TNM system?
M: Metastases: Presence of distant metastases.
