Radiation Bio. - Cancer Biology

Terms, types of cancer and their stages of it

What is cancer and where does it originate?

It originates due to DNA damage and unregulated cell division growing at any pace

Histology

Study of microscopic anatomy of cells & tissues —> tumors originate from normal tissues

Does cancer cells remain in the same place?

No, cancer moves and spreads to new places

Benign

Tumors that grow locally w/o invading tissues —> can be dangerous depending on location

Malignant

Tumors invading nearby tissues & spawn metastas

Carcinoma

• Tumors arising from epithelial

  • Squamous cell carcinomas - seal large caviaties/channels that they line, protecting the cell population; e.g., lung or skin

  • Adenocarcinomas - secrete substances into ducts/cavities they line; e.g., ovary or lung

Sarcomas

• Derived from mesenchymal cells in body

  • 1% of tumors found in oncology clinics

    • Angiosarcoma & Synovial sarcoma are two types of variety of types of common sarcomas

Hematopoietic

• Derived from blood-forming tissues/cells forming the immune system

  • Leukemia: white blood, non-pigmented

  • Lymphomas: aggregate to form SOLID tumors in lymph nodes

    • Hodgkin’s disease & Multiple myeloma

Multiple Myeloma (MM)

• Malignancy of plasma cells of B-cell lineage

  • Responsible for producing/secreting antibody molecules

Neuroectodermal Malignancies

• Tumors arisen from neutral crest

  • E.g.: Melanomas →derived from melanocytes, small-cell lung carcinomas (SCLCs)

Dedifferentiated

JUST the cells are affected of the tumor

Anaplastic

The WHOLE tumor is affected

Hyperplastic

Minimum changes seen → excessive # of cells where they shouldn’t be, they don’t necessarily FIT

A early indication of premalignant change in the esophagus is called what?

A metaplastic condition called Barrett’s esophagus

Dysplastic

• Slightly abnormal tissue

  • usually cytlogically abnormal

  • State between benign & malignent

  • “pre-cancerous” they haven’t invaded

Neoplastic

• Growths invading the underlying tissue

  • Can be benign or malignant

  • Described as cancer b/c it’s second to last in the progression of tumor growths

Monoclonal

Growths that have a single common ancestor

Polyclonal

• “growth besties”

• A mixture of different immune cell lineages (or the antibodies they produce) that respond to the same target → GOOGLE ANSWER BTW

How do we find out if tumors are monoclonal & polyclonal?

• Look at the gene glucose-6-phosphate dehydrogenase (G6PD) on X chromosome

  • Tumors ARE monoclonal

How did they prove these are tumors?

Looking at the myelomas → usually expressed in their own antibodies

Proto-oncogenous

• “Woho cancer”

• Positive growth regulators: one copy used

Tumor Suppresor

• “Boohoo cancer”

• Negative growth regulators that stop the growth

DNA Stability

• Keeps control, monitors, and maintaining integrity of DNA quality control

Metaplasia

Cell layer that migrated from where it originally started →look NORMAL

Radiation Carcinogenesis

• “creation of cancer”

  • Radiation DOES NOT lead to the formation of genetic damage, but it does increase the likelihood of genetic damage occurring → like Repair, mutations, chromosomal changes, DEATH in the cell

  • There is NO safe dose of radiation

Chromosomal changes

• Deletions - loss of genes by loss of either part or all of it

• Translocations - addition of extra genes

• Inversion - rearrangement of genes

Death of a cell defined by radiation is…

Mitotic

Somatic Cell Damage causes…

impairment of organ functions

Germ Cell Damage causes….

• Most dangerous

• Variety of birth defects

• Affect the gene pool