Despite several checkpoints in the cell cycle to check any modifications in DNA before it's transferred to next-generation, certain mutations occur in DNA, leading to the loss of certain characters and control over its multiplication rate. The consequences of these modifications result in pathological overgrowth of modified tissues, generally referred to as TUMOR or NEOPLASIA or "cancer."
The altered character of tumor cells makes them immortal, and they do not respond to the signals sent for growth regulation. Even though rapid multiplication and uncontrolled growth are common for all tumors, certain tumors are less hazardous than others. The hazardous character of tumors depends upon the metastasis nature of tumors. Metastasis is the ability of cells to separate from the mass and move through lymph or blood to invade the surrounding tissue. The tumors with metastasis are referred to as " Malignant tumors," and the tumors without metastasis are referred to as " Benign tumors."
BENIGN TUMORS:- Benign tumors are generally not harmful due to their well-defined growth with smooth boundaries that grow in diameter and are restricted to one place but can be harmful if the tumor compresses the surrounding tissue against a hard surface the body. The benign tumor usually grows at a relatively slow pace and may stop growing for a time when it reaches a certain size. A complement cure can usually be achieved by removing the abnormally grown tissue mass.
MALIGNANT TUMORS:- The malignant tumors are dreadful because their growth is not restricted to one place; their metastasis nature helps them spread from one place to other locations in the body via lymph or blood. Unlike benign tumors, it is very critical to locate and remove the malignant tumor. Generally, malignant tumors are properly referred to as " Cancers." The origin of the word cancer is credited to the Greek physician Hippocrates ( 460- 370 B.C ). IN Greek, cancer refers to a crab. It is most likely applied to the disease to mind the shape of a crab because finger-like projections spreading from a cancer tissue mass resembles the structure of crab more over the spread of cancer can be in any direction, just like the movement of a crab.
Cancers can affect all animals and people of all ages, even fetuses, but the risk for most varieties increases with age. Generally, Cancers form a tumor, but some cancers, such as leukemia blood cancer, do not form tumors, and they are referred to as " Liquid tumors. " These liquid tumors that circulate in the blood may also be from masses elsewhere in the body. Cancer causes about 13% of total deaths. According to the American cancer society, 7.6 million people died globally from cancer during 2007.
Altered biological properties of cancer cells:-
1) Acquisition of self-sufficiency in growth signals.
2) Loss of sensitivity to anti-growth signals.
3) Loss of apoptosis to grow despite genetic errors and external anti-growth signals.
4) Loss of senescence, leading to limitless replicative potential ( immortality).
5) Acquisition of sustained " angiogenesis," allowing the tumor to grow beyond the limitations of passive nutrients diffusion.
6) Acquisition of ability to invade neighboring tissue, the defining property of invasive carcinoma.
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