Paul Ehrlich was a German scientist considered the father of chemotherapy. He developed the "magic bullet" concept of targeting drugs specifically to diseased cells without harming healthy cells. Chemotherapy involves using cytotoxic drugs to treat cancer by targeting rapidly dividing cells, though it also affects other fast-dividing normal cells causing side effects like hair loss and reduced blood cell production. There are over 100 chemotherapy drugs classified into groups like alkylating agents, antimetabolites, and microtubule inhibitors that work by crosslinking DNA, blocking metabolites, or stabilizing microtubules to damage cancer cells and trigger cell death. The goals of chemotherapy include eliminating cancer, shrinking tumors, preventing spread, and relieving symptoms.

1. Prabhudas N.

2. Paul Ehrlich (1854 – 1915)
German scientist and also father of chemotherapy
Contributions:
 Salvarsan compound “magic bullet” concept
and also neosalvarsan
 methods of standardizing toxin and antitoxin
 stains to the cells and tissues
 Acid –fast stain in nature
 “Side chain theory” of antibody production

3. CHEMOTHERAPY
Systemic therapy is the main treatment available for
disseminated malignant tumor.
Progress in chemotherapy result in cure for several
tumors.
Chemotherapy usually given by drugs
in a multiple cycles.
 Medications that destroy cancer cells
 There are over 100 different chemo drugs
 One or more chemo drugs may be used to treat
different cancer.

4. • Chemotherapy involves the use of chemicals to treat cancer.
• Chemotherapeutics are cytotoxic drugs that mainly target
dividing cells.
• Therefore chemotherapy also affects cells that divide rapidly
under normal fashion.
• This includes, progenitor cells in the bone marrow, digestive
tract, and hair follicles.
• This results in the most common side-effects of
chemotherapy:
 myelosuppression (decreased production of
blood cells, hence also immunosuppression)
 mucositis (inflammation of the lining of the
digestive tract)
 alopecia (hair loss)

5. Chemotherapy drug given by
Adjuvant chemotherapy:
Chemotherapy given after surgery or irradiation to
destroy micrometastasis & prevent development of
secondary neoplasm.
Neo-adjuvant chemotherapy:
Chemotherapy given before surgery or radiotherapy
in order to diminish the volume of large primary
neoplasm.
Chemotherapeutic agents may be classified into 4 groups:
1. Alkylating agents
2. Antimetabolite
3. Anti-microtubule agent
4. Cytotoxic antibiotics

7. Alkylating agent:
• An alkylating antineoplastic agent is substance used in cancer
treatment that attaches an alkyl group (CnH2n+1) to DNA.
• The alkyl group is attached to the guanine base of DNA, at the
number 7 nitrogen atom of the purine ring.
• Cancer cells are more sensitive to alkylation than normal cells,
as their DNA repair system is inefficient.
• Most of the alkylating agents are also carcinogenic.
• Example: Cyclophospamide, Busulfan.

8. Purine ring 7 position

9. Cisplatin:
• Cisplatin is a chemotherapeutic drug that binds to guanine
residues in the DNA and cause either intra or inter-strand
crosslink.
• It is called an alkylating-like compound as it crosslinks DNA
but does not contain an alkyl group.
• The crosslinks can potential block DNA replication.
Therefore, DNA repair system is activated to remove it.
When removal of DNA lesion is impossible or incomplete,
cell death by apoptosis is induced.
• Thus, cisplatin removes cancer cell by inducing apoptosis.

11. Antimetabolite:
• These are compounds that inhibit a metabolite from
participating in a biochemical process.
• Antimetabolites are structurally similar to the natural
metabolites and are therefore called analogs.
• These compounds thus block the functioning of
biochemical reactions and pathways.
• Example: 5FU, 6 marcoptopurine and methotrexative

15. Paclitaxel (Taxol)
• This is an antineoplastic alkaloid obtained from the bark of
the tree Taxus brevifolia.
• Paclitaxel is one of several cytoskeletal drugs that
target tubulin.
• Paclitaxel-treated cells have defects in mitotic spindle
assembly, chromosome segregation, and cell division.
• Unlike other tubulin-targeting drugs such as colchicine that
inhibit microtubule assembly, paclitaxel stabilizes
the microtubule polymer and protects it from disassembly.
• Chromosomes are thus unable to achieve a metaphase
spindle configuration.
• This blocks progression of mitosis, and prolonged activation
of the mitotic checkpoint triggers apoptosis or reversion to
the G-phase of the cell cycle without cell division

18. Goals of chemotherapy
• Eliminate the cancer
• Shrink the tumor
• Prevent cancer from spreading
• Relieve symptoms from cancer, such as
pain