Types of Cancer
There are many subdivisions of abnormal cell growths in the body. The most well known division is into benign and
malignant. A benign tumor is one which is called noninvasive because it stays as a single condensed mass of abnormal
cells. A tumor becomes malignant when it begins to invade and kill off surrounding healthy tissue. A malignant tumor also has
the potential to become metastatic. This means that cancer cells detach from the main tumor and enter the blood stream
or lymphatic vessels and travel to other parts of the body to start new colonies called secondary tumors or metastases
.
Broadly speaking, cancers that originate from epithelial cells (skin cells) are called carcinomas, while cancers that originate
from connective tissue (muscle) are called sarcomas. The two types of cancer that do not originate from either skin or muscle
cells are leukemias (cancer of the blood) and neurologic cancers (cancers of nervous tissue). Most common cancers are carcinomas
because epithelial cells have the most exposure to carcinogens, cancer-causing agents.
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