Most cases of cervical cancer are caused by certain strains of the human papillomavirus (HPV), and now researchers also know the specific group of cells that HPV targets. HPV is a very common virus and is usually transmitted through sexual contact.

Researchers found that these cells become cancerous when infected with HPV while other cells in the cervix often do not, said senior author Christopher Crum, director of women’s and perinatal pathology at Brigham and Women’s Hospital in the United States.

They also have a particular gene expression that is the same as found in aggressive cervical tumours, which could allow doctors to differentiate benign lesions from dangerous pre-cancers.

“We have discovered a discrete population of cells that are located in a specific area of the cervix that could be responsible for most, if not all, of HPV-associated cervical cancers,” said Crum, who was joined by researchers Wa Xian from the Agency for Science Technology and Research (A-STAR) in Singapore and Frank McKeon of Harvard Medical School.

The cells are located near the opening of the cervix, in a transition area between the uterus and the vagina known as the squamo-columnar junction.

Linked to cancerous cells in the oesophagus

The findings build on earlier research that identified the origin of a rare and sometimes cancerous change in certain cells in the oesophagus, at a junction between the tube that carries food through the throat and the stomach.

A similar population of cells has been found to reside in the cervix, Crum said. They are the remnants of a process known as embryogenesis, which is the process of cell division and growth that we all undergo in the process of growing from embryo to foetus.

“There is a population of cells in the cervix that during foetal life disappears and is replaced by another type. We found out that a small number of these cells are actually not lost and they remained there, almost like little sentinels from a prior age,” Crum said in an AFP report.

“It appears that that particular group of remaining embryonic cells at the squamo-columnar junction is the population that you must infect, at least in the great majority of cases, to produce the significant cancers and precancers,” he added.

Possible new treatments

Knowing the biology of these cells and where they reside could help physicians both clarify which cervical precancers (dysplasias) need treatment and also possibly prevent cancer altogether by destroying the cells in advance.

Further studies may shed light on whether similar populations of cells reside in other areas of the body known to be affected by HPV-related cancers, such as the penis, vulva, anus and the throat.

Cervical cancer is the second most common cancer in South African women, and one in every 35 women in the country will be diagnosed with it in her lifetime.

Regular Pap smears can detect abnormal cells in the cervix that might become cancerous, and is an important early-detection method of cervical cancer.

Sources: Sapa, AFP, Cansa