Ch. 2: The Nature of Cancer Flashcards
What is cancer?
- Normal cell gone selfish
- Instead of performing its specific function for the good of the organism
- It takes on new function and only cares about replicating itself, doesn’t
care about the organism fitness anymore
Hallmarks of cancer
- evading apoptosis
- self-sufficiency in growth signals
- insensitivity to anti-growth signals
- sustained angiogenesis
- limitless replicative potential
- tissue invasion and metastasis
Where do cancers form?
- normal tissue
- Specialized cell types
- Progressively
- Monoclonal
- Mutagenesis
- Lifestyle/etiology
Histology
analysis of tissue sections
Sections
thin slices of tissue
What are tumors composed of?
masses of cells
What are tumors derived from?
normal tissue
Where are tumors found?
some are found in distant sites of the body
Primary tumor
The founding place
where a cancer first forms (benign-tumors that grow locally
Metastases
New tumors that form
after cancer cells have moved away from the primary tumor. (malignant-
tumors that invade nearby tissues and make new tumors)
Where do most cancers arise?
80% from epithelial cells
Carcinomas
tumors that arise from epithelial cells
Epithelia
sheets of cells that line the walls of cavities
and channels in the body. (Or the entire body- skin.)
(Examples: Gastro-intestinal tract: mouth, esophagus, stomach, small intestine, large intestine, Skin, Mammary gland, Pancreas, Lung, Liver, Ovary)
What are epithelia composed of?
similar cells, tightly packed together that form a layer
Basement membranes
Thin layer of proteins and sugars. Lie beneath epithelium. Separate epithelium from stroma.
Lumen
The cavity that a layer of epithelial cells lines
Squamous cell carcinomas
tumors that arise from
squamous shaped epithelia.
They typically seal cavities they line and protect underlying cell populations.
(Ex: cervix, skin, esophagus)
Adenocarcinomas
tumors that arise from
epithelia in an organ or gland. They typically secrete
substances into the cavities
that they line. (Ex: breast cancer, mucus secreting cells in stomach and adenocarcinomas in stomach)
Non-epithelial cancers
- sarcomas
- hematopoietic malignancies
- neuroectodermal
sarcomas
Derived from connective tissues.
- Mesenchymal cells.
- Fibroblasts- secrete collagen.
- Adipocytes- fat storing.
- Osteoblasts- form bone.
- Myocytes- form muscle.
Hematopoietic malignancies-
Derived from blood-forming
tissues, including cells of the
immune system.
ex: Leukemia- malignancy of several unpigmented blood cell lineages moving through the circulation.
ex: acute myelogenous leukemia
Neuroectodermal
Derived from central and
peripheral nervous systems.
ex: Gliomas, glioblastomas,
neuroblastomas, schwannomas,
medulloblastomas.
glioblastoma
multiforme
melanomas (what are they, derived from, and origin)
Melanocytes
(arrows) form
melanin pigment
granules extend thin
processes and
deposit granules in
the cytoplasm of
keratinocytes.
Derived from pigmented cells of
skin and retina.
Developmental origin- neural, end
up migrating and living in skin and
eyes
Teratomas (derived from, what do they do)
Derived from germ cells-
precursors to eggs and sperm
Failed to migrate during
development.
Retain ability to make all cell
types.
Tumors can differentiate into
recognizable structures (teeth,
hair, bones).
3 germ layer (outside to inside)
ectoderm -> mesoderm -> endoderm
What cancers do ectoderms form?
neuroectodermal
What cancers do mesoderms form?
hematopoietic malignancies
What layers do Carcinomas form from?
Arise from all germ layers
How cancers form progressively (steps)
A spectrum of tissue morphologies exist between normal and highly malignant
* Suggests, cancers develop in a multi-step process
1. normal
2. hyperplasia
3. dysplasia
4. in-situ cancer
5. metastatic
Monoclonal
Arise from a single cells
(most tumors are monoclonal)
Carcinogenic
Substances that cause cancer
(Many carcinogenic compounds are also mutagens)
Mutagens
substances that cause mutations in genes
(Many carcinogenic compounds are also mutagens)
Cancer is generally a ___ of mutant genes
disease
epidemiology
the study of the distribution and determinants of health and disease in specified populations
What is more important to cancer risk: your country of origin or your lifestyle?
your lifestyle
What type of cancer occurs most frequently in males?
prostate
What type of cancer occurs most frequently in females?
breast
What type of cancer causes the most deaths in males?
lung and bronchus
What type of cancer causes the most deaths in females?
lung and bronchus
Why is there a difference between genders and their cancer risks?
likely due to differences in biology, lifestyle, and culture
