In cellular biology, labile cells are cells that multiply constantly throughout life. They spend little or no time in the quiescent G0 phase

G0 phase

The G0 phase is a period in the cell cycle in which cells exist in a quiescent state. G0 phase is viewed as either an extended G1 phase, where the cell is neither dividing nor preparing to divide, or a distinct quiescent stage that occurs outside of the cell cycle...

 of the cell cycle

Cell cycle

The cell cycle, or cell-division cycle, is the series of events that takes place in a cell leading to its division and duplication . In cells without a nucleus , the cell cycle occurs via a process termed binary fission...

, but regularly perform cell division

Cell division

Cell division is the process by which a parent cell divides into two or more daughter cells . Cell division is usually a small segment of a larger cell cycle. This type of cell division in eukaryotes is known as mitosis, and leaves the daughter cell capable of dividing again. The corresponding sort...

.

This is the case for only a minority of cells in the body. Constantly dividing cell types include skin cells, cells in the gastrointestinal tract

Gastrointestinal tract

The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....

 and blood cells in the bone marrow

Bone marrow

Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...

.

In labile cells, it is not a speed-up in the segments of the cell cycle (i.e. G1 phase

G1 phase

The G1 phase is a period in the cell cycle during interphase, before the S phase. For many cells, this phase is the major period of cell growth during its lifespan. During this stage new organelles are being synthesized, so the cell requires both structural proteins and enzymes, resulting in great...

, S phase

S phase

S-phase is the part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Precise and accurate DNA replication is necessary to prevent genetic abnormalities which often lead to cell death or disease. Due to the importance, the regulatory pathways that govern this...

, G2 phase

G2 phase

G2 phase is the 3rd and final subphase of Interphase in the cell cycle directly preceding Mitosis. It follows the successful completion of S phase, during which the cell’s DNA is replicated...

 and M phase), but rather a short or absent G0 phase that is responsible for the cells' constant division.

Hazards

Constantly dividing cells have a higher risk of becoming malignant

Malignant

Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...

 and develop cancer

Cancer

Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

, dividing uncontrollably. This is why, on the other hand, muscle cancer is very rare, although constituting ~50% of body weight, since muscle cells are not constantly dividing cells.

In addition, cytotoxic drugs, such as alkylating antineoplastic agent

Alkylating antineoplastic agent

An alkylating antineoplastic agent is an alkylating agent used in cancer treatment that attaches an alkyl group to DNA.The alkyl group is attached to the guanine base of DNA, at the number 7 nitrogen atom of the purine ring....

s, used in treatment of cancer

Cancer

Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

, work by inhibiting the proliferation of dividing cells, with the malignant cells as the desired target. However, this has the adverse effect of also striking against the cells normally dividing in the body, and thus impairing normal body function of hair, skin, GI tract and bone marrow.

See also

• Stable cells, which only multiply when receiving external stimulus to do so
• Permanent cells, which don't have the ability to multiply