Cervical cancer is less prevalent in certain regions of the world, even though women in these regions have less access to cervical cancer screening and prevention programs. This may be due to cultural reasons, but also because of certain genetic factors.
A study with those findings, “Reduced rate of human papillomavirus infection and genetic overtransmission of TP53 72C polymorphic variant lower cervical cancer incidence,” was published in the journal Cancer.
Cervical cancer is a predominantly human papillomavirus (HPV)-driven disease worldwide. However, its incidence is unexplainably low in western Asia, despite the absence of screening or prevention programs against human HPV in these countries.
In the new study, Ghazi Alsbeih, MD, PhD, of the King Faisal Specialist Hospital & Research Centre in Saudi Arabia, and colleagues assessed the HPV infection rate and investigated how genetic variations of a known tumor suppressor, TP53, could influence the risk for HPV-driven cancers.
Researchers gathered tumor samples and socio-demographic information from 232 women with invasive cervical cancer, and compared them with 313 women without cancer in Saudi Arabia.
They found that these women had two peaks of higher incidence of cervical cancer, at ages 43 and 61 years.
“As cancer development takes years to decades, the first peak could be a consequence of early sexual encounters, which often occurs at the end of the teenage period to the early thirties, while the second rebound could correspond to new encounters later in life,” Alsbeih, lead author of the study, said in a press release. “The latter is generally occasioned by separation, failure of a first marriage, or simply second marriages in polygamous societies, which brings in an added risk of HPV infections as the number of lifetime sexual partners increases.”
While globally 85% to 99% of women with cervical cancer test positive for HPV infection, the researchers found that in this study sample only 77% were HPV-positive.
The researchers also found that HPV-negative patients were more likely to have a specific genetic variant in the p53 tumor suppressor gene.
They believe this genetic variant could be linked with a reduced probability for HPV infection, which subsequently is associated with a decreased risk for cervical cancer.
This genetic variant was more common in this group than it is in populations from other parts of the world that show higher incidences of cervical cancer.
While saying that this genetic variant may be a protective factor against cancer may be provocative, the researchers contend that differing cultural norms also may explain the lower cervical cancer rates in Saudi Arabia.