• Types of tumor
o Loss of polarity
• Cancer is a disease in which cells, almost anywhere in
the body, begin to divide uncontrollably and has the
ability to spread.
• A tumor is when this uncontrolled growth occurs in solid
tissue such as an organ, muscle, or bone.
4. Types of tumor
• There are two types of solid tumors: malignant
(cancerous) and benign (noncancerous).
• Cancerous tumors can invade nearby tissues in the body
and may travel to other places (metastases).
• Anaplasia used to describe cells that have lost the
unique characteristics that define them as a certain
• the word means “to form backwards” in the sense that
normal cells become more specialized with each
• Anaplasia can be explained as when a cell ‘reverts’ to a
more stem-cell like state, one that is often distorted.
• Often seen in cancer cells, the cell no longer functions
as part of the tissue that surrounds it.
• Pleomorphism is a term used in histology and
cytopathology to describe variability in the size, shape
and staining of cells and/or their nuclei.
• Therefore, cellular and nuclear pleomorphism is one of
the earliest hallmarks of cancer progression.
10. Loss of polarity
• Cell polarity is a fundamental feature of many types of
cells. Epithelial cells are one example of a polarized cell
type, featuring distinct 'apical', 'lateral' and 'basal' plasma
11. Loss of polarity
• Loss of cell polarity and subsequent tissue
disorganization is a hallmark of cancer.
• Recent evidence supports that disruption of cell-polarity
mechanisms plays a causal role in tumor initiation.
• Before cancer cells form in tissues, the cells go through
abnormal changes hyperplasia and dysplasia.
• In hyperplasia, there is an increase in the number of
cells but appear normal under a microscope.
• In dysplasia, the cells look abnormal under a microscope
but are not cancer. Hyperplasia and dysplasia may or
may not become cancer.
• A group of abnormal cells that remain in the place where
they first formed. They have not spread. These abnormal
cells may become cancer and spread into nearby normal
tissue. Also called stage 0 disease.
• A cancer is an abnormal growth of cells (usually derived from a single
abnormal cell). The cells have lost normal control mechanisms and thus are
able to multiply continuously, invade nearby tissues, migrate to distant parts
of the body, and promote the growth of new blood vessels from which the
cells derive nutrients. Cancerous (malignant) cells can develop from any
tissue within the body.
• The term tumor refers to an abnormal growth or mass. Tumors can be
cancerous or noncancerous. Cancerous cells from the primary (initial) site
can spread throughout the body (metastasize).
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