- Recently, doctors in Japan reported two cases of infants contracting tumor cells from their mothers likely during birth.
- Mothers of both infants had undetected cervical cancer at the time of delivery.
- The researchers recommend birth via cesarean section in pregnant women with cervical cancers.
According to the World Health Organization (WHO), cervical cancer is the fourth most common cancer among women. Almost all cases occur as a result of infection with the human papillomavirus (HPV). Although mother-to-infant transmission of cancers is rare, there have been reports of cancer cells moving across the placenta and into the fetus. However, for the first time doctors have found evidence of vaginal transmission of cancer cells during birth.
The report, published in the New England Journal of Medicine, describes the case of two infants who developed lung cancers as a result of vaginal transmission of tumor cells from their mothers.
Cervical Cancer Cells Transferred During Birth
The boys aged 23 months and 6 years, both had mothers with undetected cervical cancer at the time of delivery. The doctors in Japan believe the infants likely aspirated the fluid containing cancer cells.
In our cases, we think that tumors arose from mother-to-infant vaginal transmission through aspiration of tumor-contaminated vaginal fluids during birth.
Dr. Ayumu Arakawa, lead researcher
The first patient, aged 23 months, was discovered when doctors investigated his chronic cough. Although his mother had a negative pap smear before birth, she received a diagnosis of cervical cancer three months after the delivery.
The second patient presented with chest pain at 6 years of age and was later diagnosed with lung cancer. Although the mother had a cervical tumor at the time of delivery, a cervical cytologic test had revealed it was benign. She later developed cervical cancer and died 2 years later.
Both infants underwent successful cancer treatment and are alive and doing well.
How Did They Make the Discovery?
According to the report a slow tumor growth in one child and the spontaneous regression of lesions in the other had causes doctors to suspect an alloimmune response. Furthermore, in one of the infants, the tumor responded well to immune checkpoint inhibitor therapy with nivolumab.
After routine genetic testing of samples from infants and mothers showed similar histological patterns, doctors confirmed vaginal transmission of cancer cells. Additionally, tumors in both the infants were positive for HPV.
Transplacental transmission usually results in metastases to the brain, bones, liver, and soft tissue. However, the infants only presented with tumors in the lungs and along the bronchi. Thus, suggesting that they likely aspirated the maternal cancer cells present in vaginal fluid during delivery.
Mother-to-infant transmission of the tumor may be a risk of vaginal delivery among women with cervical cancers. Cesarean section should be recommended for mothers with uterine cervical cancer.
Dr. Ayumu Arakawa, lead researcher
The report provides evidence of vaginal transmission of uterine cervical tumors. Researchers believe the genetic sequencing of samples from both infants and mothers can serve as an important diagnostic tool.
Reference:
Arakawa, Ayumu, et al. “Vaginal Transmission of Cancer from Mothers with Cervical Cancer to Infants.” New England Journal of Medicine, vol. 384, no. 1, 2021, pp. 42–50., doi:10.1056/nejmoa2030391.
