BENIGN AND MALIGNANT TUMORS − Rakyat Biologi

The solid mass of uncontrolled cell growth is known as tumor.

Tumors are of two types:

1. Benign tumors: These are slow growing mass of neoplasm cells [cancer cells are known as neoplasm], which compresses the surrounding tissue (giving capsulated appearance) but never metastasizes to distant organs.[metastasis means lodgement or spread of neoplasmic cells to the nearby and distant organs, organs other than the origin of the tumor cells].They have good prognosis. The neoplasmic cells resemble the cells of the parent organ. As the proliferation of the cells occur by mitosis, benign tumors have fewer mitotic figures than the malignanat tumors.

2. Malignant tumors [cancer]: These grow rapidly, invade the surrounding tissues [grow into the surrounding tissue and destroy them] and metastasizes to distant organs [lymph and blood are the route of metastasis, lymph being the most common route of metastasis]. They usually have bad prognosis. The cells have more mitotic figures than the benign neoplasm. The cells of malignant tumor are morphologically and functionally different from the normal cells and the tumor cells are less organized than the cells of the parent organ.

Carcinogenes: The substances or the agents causing cancer are known as carcinogens. Aflatoxins produced by Aspergillus, tobacco [tar of cigarette], betel nut (causes oral cancer), smoke, high energy radiations (gamma rays, x-ray, uv ray and alpha particles), chemicals (benzopyrines, inhaled asbestos, cadmium, nickel, vinyl chloride, nitrosamine, benzene etc), infectious agents/(viruses and bacteria [Helicobacter pylori causes stomach cancer]).