Treatment

Question 1

Surgery

Answer 1

oPartial mastectomy for localised tumour
oTotal mastectomy (removal of all breast) if tumour has spread. Lymph nodes may be removed if tumour has metastasised.
• Radiation therapy
• Chemotherapy
• Hormonal (biologic) therapy
oIf tumour has hormone receptor involvement (ER & HER2), effects/ formation of oestrogen is blocked.

Question 2

Molecular cell cycle

Answer 2

The cell cycle (cell-division cycle) is the process by which a single mother eukaryotic cell gives rise to two identical daughter cells.
Most cells have a finite capacity for division and can become senescent at any time; senescence is the process by which cells irreversibly stop dividing and enter a state of permanent growth arrest without undergoing cell death. Senescent cells sit within the tissue and change the plasticity of the tissue – the longer they sit around, can be promoting a cancer.

Question 3

Cycle Stages:

Answer 3

The cell cycle is composed of interphase (G₁, S, and G₂ phases), followed by the mitotic phase (mitosis and cytokinesis), and G₀ phase.
During interphase, the cell grows and makes a copy of its DNA. During the mitotic (M) phase, the cell separates its DNA into two sets and divides its cytoplasm, forming two new cells.

Question 4

Events of the cell-cycle

Answer 4

E2F is a group of genes that encodes a family of transcription factors (TF) in higher eukaryotes.

Question 5

Interphase G1

Answer 5

During the first gap phase, the cell grows physically larger, copies organelles, and makes the molecular building blocks it will need in later steps. The availability of growth factors controls the animal cell cycle at a point in late G1 called the restriction point; if growth factors are not available during G1, the cells enter a quiescent stage of the cycle called G0.

Question 6

Interphase S

Answer 6

The cell synthesizes a complete copy of the DNA in its nucleus. It also duplicates a microtubule-organizing structure called the centrosome. The centrosomes help separate DNA during M phase.

Question 7

Interphase G2

Answer 7

During the second gap phase, the cell grows more, makes proteins and organelles, and begins to reorganize its contents in preparation for mitosis. G2 ends when mitosis begins

Question 8

Mitotic (M) phase

Answer 8

During the mitotic (M) phase, the cell divides its copied DNA and cytoplasm to make two new cells. M phase involves two distinct division-related processes: mitosis and cytokinesis.
•In the prophase of mitosis, chromosomal material condenses to form compact mitotic chromosomes. The cytoskeleton is disassembled, and mitotic spindle is assembled.
•In the prometaphase, the chromosomal microtubules attach to kinetochores of chromosomes and are moved to the spindle equator.
•In the metaphase, chromosomes are aligned along the metaphase plate and are attached to both poles by microtubules.
•In the anaphase the centromeres split, and chromatids separate moving the chromosomes to opposite single poles.
•In the telophase, the chromosomes cluster at opposite poles. The nuclear membrane assembles around the clusters, with daughter cells formed by cytokinesis.

Question 9

Non-mutagenic…

Answer 9

Non-mutagenic replication of every nucleotide once per cycle is essential; only one copy should be made, with no mutations

Question 10

DNA is made up of 4 nucleotide monomers, distinguished by their bases:

Answer 10

•	Purines:
o	A - adenine
o	G – guanine
•	Pyrimidines:
o	T - thymine
o	C - cytosine

Question 11

Radiolabelled nucleotides (3H-thymidine):

Answer 11

Radiolabelled nucleotides (3H-thymidine) are incorporated into cells at DNA replication. Using X-ray photography or antibody staining, cells in S-phase may be identified. Flow-cytometric detection of cells stained with DNA dyes allows the discrimination of cells with variable DNA content. Cells in G1 phase (peak 1) contain half the DNA of cells after DNA replication in G2 and M (peak 2); cells in the process of replication (S-phase) contain an intermediate quantity