The Face Of A Cancer Cell

By: Dr Tan Puay Hoon Senior Consultant,
Dept of Pathology, Singapore General Hospital

What does a cancer cell look like and does it have a unique face?
In order to recognize a cancer cell, we need to be familiar with what makes a normal cell. A cell consists of a nucleus that contains the genetic matter, and cytoplasm which holds its organelles within a liquid environment. The nucleus has a small nucleolus that is involved in protein synthesis.

The structure or form of a cancer cell results from underlying aberrant genetic changes that it has undergone. Its features are best appreciated with the light microscope, and in general, a cancer cell will show an enlarged nucleus reflecting the accumulation of abnormal genetic material, and a conspicuous nucleolus indicating increased cell activity. Other typical alterations are nuclear pleomorphism, referring to variation in nuclear size and shape; and hyperchromasia, which also results from excess genetic material contained in its chromatin. Often, a cancer cell is described as revealing a high nuclear-cytoplasmic ratio, essentially implicating enlargement of the nucleus that occupies more of the individual cell volume. There is also increased mitotic activity, reflecting rapid proliferation and growth of the cancer cells; abnormal mitoses such as tripolar mitoses may be seen. These characteristics of a cancer cell are termed anaplasia.

Just as symmetrical and regular features lead to a pleasant face, anaplasia in a cancer cell is contemplated as ugly.

How do we tell a cancer cell from a normal or benign cell?
A normal or benign cell will not have the described abnormal changes. It will instead appear regular in shape and size, and the nucleus will generally have smooth contours. The chromatin is fine and the nucleolus inconspicuous. The nuclear-cytoplasmic ratio is not increased, and if mitoses are discovered, they are normal in appearance.

There are some cancer cells that are very well-differentiated, such that their appearances mimic that of benign cells. In such instances, other associated features of cancer are used to corroborate a malignant diagnosis.

Do cancer cells have a recognisable relationship with its environment?
Cancer cells have the ability to invade the surrounding tissues. They form tongue-like groups and nests that permeate the stroma, sometimes even extending into blood vessels. The appearance of this irregular invasion is the underlying reason for its being called “cancer” which is derived from the latin word for “crab”.

Are there other associated features of cancer cells?
Since cancer cells grow very quickly, they can outstrip their blood supply, resulting in necrosis or cell death. There is haemorrhage or bleeding, due to new vessel formation accompanying the cancer growth, or destruction of vessel walls by the invading cancer cells.The connective tissue in which cancer cells sit can respond by evoking a “desmoplastic” reaction, which features loose fibroblastic stromal cells surrounding the cancer cell nests.

The ability of cancer cells to invade blood vessels allows them to circulate and “metastasize” to other organs and tissues of the body, distant from the site of origin.

Conclusion
The cancer cell, while usually showing a fairly characteristic face, may sometimes assume less familiar appearances. It is important to understand that the cancer cell may have another countenance, and that a definitive diagnosis of malignancy relies on the careful interpretation of tissue and cell material by a pathologist.