Life history of a breast cancer cell

Robert Gagliano, M.D.

Breast cancer results from a series of damaging changes over time in the genes (DNA) of a normal breast cell. Viruses, chemicals, or radiation all damage a cell’s genes and initiate the cancer process. Hormones can promote the process.

Cells divide geometrically, that is one cell becomes two, then four, eight, 16, 32 and so forth. Spontaneous DNA damage (mutations), a mistake in cell division, occurs in about one out of every million breast cancer cell divisions.

Eventually the accumulated genetic changes in these cells results in uncontrolled cell division and growth (malignancy). Microscopic amounts of cancer cells can survive by absorbing oxygen and sugar fuel (glucose) from nearby normal cells. After 20 cell divisions the tumor size is about 1/25 inch, or a million cells. Now it will need a blood supply for oxygen and glucose to sustain further growth.

The cancer cells may make molecules in order to provide a blood supply. Once the tumor gets a blood supply, cancer cells are capable of spreading in the bloodstream from the breast to other organs (metastasis). This sequence of events can occur repeatedly resulting in a large number of metastasis in many different organs.

Once a tumor has doubled 30 times and reaches a billion cells, or ½ inch in size, it may be detectable by tumor marker blood tests, mammography, CT scans or MRI.

The bigger a tumor gets, more mutations will accumulate in the original cancer cells offspring. The mutations give new and fearsome properties to the breast cancer cells: immortality, the ability to evade the body’s immune system, more rapid and successful organ spread and invasion, and most importantly resistance to radiation, chemotherapy, hormones and biologic therapy.

Once the microscopic spread of resistant breast cancer cells occurs, the disease may be incurable. This explains why some patients die from breast cancer even when the surgeon “got it all.” It explains why cancer specialists frequently recommend radiation, chemotherapy, hormone or biologic treatment after all the obvious cancer has been removed. These features explain why many breast cancers are difficult to treat and might not be cured.

Finally, this explains why detecting a breast cancer in its earliest stages when it is small with routine screening mammograms is of paramount importance. Early detection affords the best chance for cure before drug or radiation resistance occurs.

Modern breast cancer therapies employ many innovative strategies at various stages of a cancer’s life cycle to defeat its capabilities of uncontrolled growth, spread, and resistance to treatment.

- Surgery or radiation therapy can cure many localized early stage breast cancers or “debulk” larger cancers making “micrometastasis” more susceptible to chemotherapy, hormones or biologics.

- “Angiogenesis inhibitors” can kill a tumor’s blood supply and starve it of oxygen and glucose.

- Combinations of different chemotherapy drugs, biologics or hormones can be used simultaneously to overcome drug resistance.

- Radiation and chemotherapy can kill breast cancer cells by directly damaging the cells’ DNA or interfering with key metabolic processes of cell division.

- “Monoclonal antibodies” may target a cancer cells outer protective membrane.

- Hormones can put cancer cells in a non-dividing dormant phase of their life cycle.

Patients with localized early stage breast cancers today can anticipate 75%-95% cure rates! Indeed, early detection cannot be repeated too many times.

Robert Gagliano, M.D., is board certified, specializing in Cancer/Hematology. Dr. Gagliano has more than 30 years experience in treating cancer patients. He has participated in many clinical trials and studies.