Comprehensive Cancer Study Guide: Types, Cell Processes, and Treatments

Cancer

The second leading cause of death in the U.S.

Cancer deaths and diagnoses in 2018

609,640 deaths and 1,735,350 new diagnoses.

Most common cancer overall in the U.S.

Skin cancer.

Most common cancer in men

Prostate cancer.

Most common cancer in women

Breast cancer.

Cancer with the highest mortality rate for both sexes

Lung cancer.

Key processes of normal cell renewal and repair

Proliferation, differentiation, apoptosis.

Proliferation

Cell division to replace old cells or provide new ones when needed.

Differentiation

The process by which cells become more specialized with each mitotic division.

Apoptosis

Programmed cell death of old, damaged, or unneeded cells.

Proto-oncogenes

Genes that signal for controlled proliferation.

Mutation of proto-oncogenes

They become oncogenes and drive uncontrolled cell growth.

Tumor suppressor genes

Inhibit cell growth and promote apoptosis when necessary.

Damage to tumor suppressor genes

Unregulated growth and potential cancer formation.

Phases of the cell cycle

G1, S, G2, M.

G1 phase

DNA synthesis stops, RNA and protein synthesis begin.

S phase

DNA replication occurs.

G2 phase

DNA synthesis stops, RNA and protein synthesis continue.

M phase

Mitosis and cytoplasmic division.

G0 phase

Resting phase when cells leave the cycle; some reenter, others (like neurons) stay permanently.

Cell cycle checkpoints

Surveillance mechanisms ensuring DNA is replicated and repaired before the cell progresses.

Gametes

Haploid cells (sperm, ovum).

Somatic cells

Diploid, body-forming cells.

Categories of proliferating cells

(1) Well-differentiated non-dividing cells (neurons, skeletal/cardiac muscle). (2) Progenitor cells that reproduce (skin, blood, liver). (3) Stem cells that can produce progenitor cells.

Role of stem cells

Provide self-renewal and potency (pluri-, multi-, unipotent).

Oncology

Study of neoplasms ("onkos" = swelling).

Neoplasm

New, uncontrolled growth of abnormal tissue.

Benign neoplasms

Well-differentiated, slow-growing, localized, encapsulated; may cause problems by compression or hormone secretion.

Malignant neoplasms

Poorly differentiated, fast-growing, invasive, metastasizing tumors.

Categories of malignant tumors

Solid tumors and hematologic cancers.

Traits distinguishing benign vs malignant neoplasms

Cell characteristics, growth rate, mode of growth, metastasis potential, lethality.

Naming tumors

By adding "-oma" to the tissue type (e.g., adenoma, lipoma).

Adenoma

Benign tumor of glandular epithelium.

Osteoma

Benign bone tumor.

Papilloma

Benign surface growth with finger-like projections.

Carcinoma

Malignant epithelial tumor.

Adenocarcinoma

Malignant glandular epithelial tumor.

Sarcoma

Malignant mesenchymal tumor.

Carcinoma in situ

Pre-invasive lesion localized to epithelium; curable if removed.

Anaplasia

Loss of differentiation in cancer cells ("backward formation").

Pleomorphism

Variation in cell/nuclear size and shape.

Tumor grading

Classification based on differentiation: Grade I = well-differentiated; Grade IV = anaplastic.

Genetic instability

High mutation rates in cancer due to defects in DNA repair.

growth factor independence

Cancer cells proliferate without external growth factors.

contact inhibition

Normal cells stop growing when crowded; cancer cells lose this property.

anchorage dependence

Normal cells need attachment to grow; cancer cells do not.

telomerase

Enzyme that gives cancer cells unlimited lifespan.

tumor antigens

Abnormal surface proteins that can serve as cancer markers.

direct invasion

Local spread into surrounding tissue.

seeding

Shed cancer cells enter body cavities (common in ovarian cancer).

metastasis

Spread of cancer to distant sites via lymphatics or blood.

sentinel node

First lymph node that drains a tumor area.

angiogenesis

Formation of new blood vessels to support tumor growth.

growth fraction

Ratio of dividing cells to resting cells.

doubling time

Time it takes for tumor mass to double.

point mutation

Single nucleotide change (e.g., ras gene → oncogene).

chromosomal translocation

DNA rearrangement (e.g., Burkitt lymphoma, CML).

gene amplification

Multiple copies of a gene (e.g., HER2/neu in breast cancer).

key molecular defects linked to cancer

DNA repair defects, signaling pathway defects, apoptosis evasion, senescence bypass, angiogenesis, invasion.

stages of transformation

Initiation (irreversible DNA damage), Promotion (reversible proliferation), Progression (malignant change).

inherited genes increasing breast/ovarian cancer risk

BRCA1 and BRCA2.

link between obesity and cancer

Insulin resistance, ↑ insulin, ↑ sex hormones, chronic inflammation.

hormone-related cancers

Breast, ovarian, endometrial, prostate.

immune suppression effect on cancer risk

↓ T-cell surveillance increases malignancy risk (e.g., Kaposi sarcoma in AIDS).

chemical carcinogens

Direct-acting (active immediately) or indirect (require metabolism).

lifestyle factors increasing cancer risk

Smoking, alcohol, diet (high fat/red meat, low fiber), obesity, inactivity.

radiation types increasing cancer risk

Ionizing (atomic bomb survivors), UV radiation (skin cancer).

oncogenic viruses

HPV, EBV, HHV-8, HBV, HCV.

tissue-related signs of cancer

Ulceration, necrosis, bleeding.

cancers presenting with pleural effusion

Lung, breast, lymphoma.

cancer cachexia

Wasting syndrome with weight loss, anorexia, anemia.

common systemic effects of cancer

Fatigue, anemia, wasting.

paraneoplastic syndromes

Distant effects of cancer (e.g., SIADH, Cushing's, hypercalcemia).

main cancer screening methods

Observation, palpation, Pap smear, mammography, colonoscopy.

tumor markers

Antigens, hormones, or proteins elevated in cancer (e.g., PSA).

limitations of tumor markers

Non-specific; may be elevated in benign conditions or absent early in disease.

Pap test

Used for detecting abnormal cervical cells.

immunohistochemistry

Identifying cell markers and guiding therapy (e.g., ER+ breast cancer).

TNM system

Classification by Tumor size (T), Node involvement (N), Metastasis (M).

three goals of treatment

Curative, control, palliative.

five main treatment types

Surgery, radiation, chemotherapy, hormonal therapy, biotherapy.

side effects of radiation therapy

Skin irritation, bone marrow suppression.

side effects of chemotherapy

Bone marrow suppression, GI upset, alopecia.

hormonal therapy drugs

Tamoxifen (antiestrogen), flutamide (antiandrogen).

examples of monoclonal antibodies in biotherapy

Rituximab (CD20), Bevacizumab (VEGF), Cetuximab (EGFR).

Neoplasia

New, uncontrolled growth leading to a neoplasm (tumor).

Cell Proliferation

Maintains tissue balance by ensuring new cells equal lost cells.

Stem Cells

Incompletely differentiated cells that can produce new stem cells and specialized progenitor cells.

Self-renewal

The ability of stem cells to divide repeatedly while remaining undifferentiated.

Potency

The ability of stem cells to differentiate into various cell types.

Pluripotent

Stem cells that can differentiate into any cell type.

Multipotent

Stem cells that can differentiate into a limited range of cell types.

Unipotent

Stem cells that can differentiate into one type but can self-renew.

Solid tumors

Begin in tissue/organ, invade locally, and spread via blood/lymph (metastasis).

Hematologic cancers

Blood/lymph cancers that are already systemic.

Benign tumors

Usually end in '-oma.'

Malignant tumors

Usually named carcinoma (epithelial origin) or sarcoma (mesenchymal origin).

Squamous cell carcinoma

Malignant tumor arising from squamous epithelium.

Fibroma

Benign tumor of fibrous tissue.

Fibrosarcoma

Malignant tumor of fibrous tissue.