6.Acquired Predisposing Conditions to Cancer — Study Note

1. Major Categories of Acquired Cancer Risk

Acquired (non-inherited) biological states that increase malignancy risk fall into three broad groups:

1. Chronic inflammation
2. Immunodeficiency states
3. Precursor lesions

These conditions → increase mutation risk, cell turnover, and reduce immune control, promoting neoplastic transformation.

2. Chronic Inflammation

Why chronic inflammation predisposes to cancer

• Persistent injury → repeated cell proliferation
• Accumulated DNA damage due to:
• ROS and reactive nitrogen species
• cytokines + growth factors promoting survival and proliferation
• Increased cell turnover increases mutation probability

Main associated cancers

• Mostly carcinomas (epithelial malignancies)
• Also mesothelioma
• Selected lymphomas

Concept: inflamed tissues provide a microenvironment favoring malignant transformation.

3. Immunodeficiency States

How immune failure increases cancer risk

• Immune system normally provides tumor surveillance → removes emerging malignant clones
• Deficiency weakens surveillance → malignant cells survive

Higher risk for:

• Virus-driven malignancies (viruses act as oncogenic triggers)
• Examples:
• lymphomas
• carcinomas
• sarcoma-like proliferations

4. Precursor Lesions

Definition

• Localized epithelial abnormalities associated with increased risk of malignancy.

Causes / associations

• Chronic inflammation
• Hormonal disturbances (e.g., prolonged unopposed estrogen exposure)
• Spontaneous genetic mutations

Progression risk

• Do not always progress to cancer
• But removal or management reduces cancer risk

Molecular link

• Many precursor lesions already contain early cancer-associated mutations
• Represent “early steps” toward invasive cancer

5. Examples of Precursor Lesions & Associated Cancers

Mnemonic: SELV

• S – Squamous dysplasia → Lung cancer
• E – Endometrial hyperplasia → Endometrial cancer
• L – Leukoplakia → squamous cancers
• V – Villous adenoma → colorectal cancer

6. Malignant Change in Benign Tumors

Key concept

• Not all benign tumors are precancerous.
• Malignant risk varies by tumor type.

Examples

• Colonic adenomas: significant malignant potential (up to ~50% risk; risk ↑ with size and villous pattern).
• Uterine leiomyomas: malignant transformation extremely rare.

Simple memory contrast:

• Adenomas → precancerous
• Leiomyomas → benign stability

7. Summary Table — Acquired Predispositions

Mnemonic Wrap-Up — “HIP-Risk”

• Hyperplasia (endometrial)
• Inflammation (chronic)
• Precursor lesions
• Risk varies in benign tumors
• Immunodeficiency
• Squamous metaplasia/dysplasia
• Kolonic adenoma (villous = high risk)

Final take-home concepts

• Acquired tissue stresses can enable cancer even without inherited mutations.
• Chronic inflammation, immune compromise, and precursor epithelial changes are major warning conditions.
• Early detection and removal of precursor lesions prevents many cancers.