Neoplasia Flashcards
Describe the 2 components of tissue renewal and repair
- Proliferation (cell division): inherent mechanism when old cells die or more cells are needed
- Differentiation: cells become specialized in structure and function to replace old cells
Describe proliferation and differentiation in neoplasms
Benign: well-differentiated cells but no control over proliferation
Malignant: less differentiated to undifferentiated and no control over proliferation and differentiation.
What types of tissues compose neoplasms?
- Parenchymal (specific functional cells)
- connective (forms support network or stroma that contains blood supply)
What is the name of a benign epithelial tumor of glandular tissue?
Adenoma
What is the name of a malignancy that arises from glandular tissue?
Adenocarcinoma
What is a sarcoma?
Malignant tumors of mesenchymal origin
What is a fibrosarcoma?
Malignant tumor of fibrous connective tissue (mesenchymal)
What is a chondrosarcoma?
Malignant tumor originating from chondrocytes
What is a papilloma?
Benign micro or macroscopic fingerlike projections that can grow on any surface
Polyp = growth projecting from mucosal tissue
Differences between benign and malignant tumors
- Characteristics of tumor cells
- Rate of growth
- Local invasion
- Ability to metastasize
True or false: benign tumors can spread by metastasis
False
How do benign and malignant tumors differ in their mode of growth?
Benign: expands without invading other tissues and usually encapsulated by CT
Malignant: Invades surrounding tissues
The more undifferentiated the cells, the _________ rapid the rate of growth
More
What are 2 types of malignant neoplasms?
- Solid tumors: confined to a tissue or organ but can metastasize
- Hematologic cancers: found in blood and lymph
How are malignant neoplasms that are poorly differentiated or undifferentiated described?
Anaplastic
What is the condition in which cells and nuclei vary in size and shape?
How does this affect the cell?
Pleomorphism
Chromatin is clumped and there are a large number of mitoses in the nucleus.
How does the cancer grading system work?
The closer the tumor cells resemble normal tissue cells both structurally and functionally, the lower the grade.
Grades I-IV:
Grade I: well-differentiated
Grade IV: poorly differentiated and marked anaplasia
In wound healing, fibrous tissue growth stops when edges of a wound come together. What is this referring to and how does it apply to cancer?
Contact inhibition or cell density-dependent inhibition.
Malignant cells do not have contact inhibition and grow rapidly despite coming into contact with adjacent tissues
Why can malignant cells be found in body fluids and be detected by cytologic examination?
Malignant cells lose cell adhesion molecules and can therefore shed into the surrounding body fluids
What is anchorage independence?
Malignant cells can grow in “abnormal” environments without a “home” ie they don’t need to attach to a solid surface like the ECM to grow and divide.
How do changes in gap junction proteins impact cancer cells?
They lose their cell-to-cell communication due to disturbance of cytoplasmic continuity and do not receive normal signals.
How are cancer cells able to be immortal?
They can divide infinitely because they have high levels of telomerase, which prevents telomere shortening. Shortened telomeres are associated with cellular replicative senescence.
What is the risk of surgical removal of cancers?
They may inadvertently cause cancer cells to seed into body cavities, commonly the peritoneal cavity.
True or false: Lymphatic spread is more typical of sarcomas
False. Lymphatic spread is typical of carcinomas. Hematogenous spread is typical of sarcomas.
How do metastatic cells in the lymph gain access to the circulatory system?
Through the thoracic duct
How does breast cancer usually spread?
Through the lymph (it is a carcinoma)
Sentinel node
First lymph node that the primary tumor cells drain into
What types of blood vessels are most at risk in hematogenous spread?
Capillaries and venules because they have thinner walls
What are the most common metastatic sites of hematogenous spread?
The liver and lungs.
Venous blood from the GI, pancreas, and spleen is routed through the portal vein to the liver and all vena cava flows to the lungs
How are cancer cells able to enter the blood in the first place?
They secrete enzymes that break down the ECM of the tissue and then they can invade the blood vessels
What is needed for angiogenesis?
Angiogenesis is the process of developing new blood vessels within the new tumor.
Specific growth factors are needed
What are molecular mechanisms involved in the development of cancerous cells?
- Mutations in genes that normally repair damaged DNA
- Increase in growth factor signaling pathways
- Evasion of apoptosis
- Development of sustained angiogenesis through loss of angiogenic inhibitors or increase in proangiogenic factors.
- Sustained invasion and metastasis
Describe the 3 steps to the transformation of a normal cell into a cancer cell by a carcinogenic agent
- Initiation: cells are exposed to a carcinogenic agent that causes malignant transformation.
- Promotion: induction of unregulated accelerated growth by chemicals and growth factors.
- Progression: tumor cells acquire malignant phenotypic changes.
Proto-oncogene
A gene that codes for proteins that have a role in the cell cycle
Oncogene
A gene that causes cancer
