Cancer is characterised by an abnormal, uncontrolled growth that may destroy and invade adjacent healthy body tissues or elsewhere in the body (secondary spread - secondary deposits secondaries - metastases). 

Living organisms (all animals and plants) are made of cells. The simplest organisms consist of just a single cell. Each cell has a central control, the nucleus surrounded by cytoplasm (Fig. 21.2). The nucleus contains the genes, which are the biological blueprints that control the structure and function of the organism. The genes are the chromosomes each human cell has twenty-three pairs. Each chromosome is composed of DNA (Deoxyribose nucleic acid) and the DNA is a string of nucleotides. There are four nucleotides (A, C, G and T). The genetic code is a long string of these nucleotides grouped in threes e.g. ACG, TTT, CAG etc. The analysis of the human genetic coding has reached completion. It has been suggested that the full code would require 40 large volumes using a standard print size.

The human body has billions of cells (Q 2.1). Most cells have a limited life-span and need to be replaced. Cells are capable of duplicating themselves. Before birth and through childhood our bodies grow mainly through increase in cell numbers. The body's cells are dividing throughout life. The red blood cells, for example, only survive for 120 days about one per cent of the circulating red cells are therefore replaced each day. Little is currently known about how the cells are replaced in such an orderly and precise fashion. Fundamental to the process is the doubling of the chromosomes (mitosis) during cell replication so that each new cell has an exact copy of the chromosomes laid down in the original egg at the time of fertilisation. There are natural mechanisms that speed up the process if there has been an excessive amount of cell loss: for example, following blood loss the process of red blood cell replacement is temporarily increased.

Millions of cell divisions and replications occur daily in the body and it is astounding that the process occurs so perfectly most of the time every cell division requires replication of the 40 volumes of genetic coding. On rare occasions there is some defect in a division and a rogue (mutant), potentially malignant cell arises. The immune system seems to recognise such occurrences and is generally capable of removing the abnormal cells before they have an opportunity to proliferate. Rarely, there is a failure of the mechanism and a potentially malignant cell survives, replicates and cancer is the result.

The four more common female cancers have their origins in the ovaries, body of the uterus, cervix of the uterus and breast, and they strike at the heart of femininity and sexuality.

Women's Health

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