It is not impossible for a baby to get cancer from their mother, but it does not happen very often.
Researchers estimate that the transmission of maternal cancer to children occurs probably only twice in every million births for mothers with cancer, with the diseased cells being delivered to the baby through the placenta in those very rare and unfortunate cases.
But that’s not the only way a mother with cancer could unknowingly give birth to her baby, scientists say.
In a new case study published by researchers in Japan, doctors report what appears to be the first medical: vaginal transmission of cancer cells from mothers with breast cancer to babies at birth.
“It is theoretically possible to transmit mother-to-child tumors in the birth canal during vaginal delivery,” the researchers, led by pediatric oncologist Ayumu Arakawa of the National Cancer Center Hospital in Tokyo, said. explains in their paper.
“If the mother has breast cancer, the baby can be exposed to tumor cells in fluids in the birth canal and could enter tumor cells into the lungs.”
This is how the mother’s tumor cells were delivered to the baby’s lungs at birth. pic.twitter.com/8r8xXKcb4Q
– Takashi Kohno @ Natl Cancer Ctr, Japan (@ TakashiKohno2) 7 January 2021
This obscure and previously unknown vector – including cancer in your first breath, seems to be responsible for two unrelated cases of pediatric lung cancer that have been diagnosed. confirmed in a pair of young male patients: age 23 months and six years -old.
In each case, the patients were taken to the hospital with symptoms of the disease, the 23-month-old suffered a cough, and the six-year-old suffered a chest pain.
In each case, CT scans revealed what ended up as cancerous tumors in the boys’ lungs, which were successfully treated in all cases – though not easily.
Both young patients received chemotherapy strokes again, but were only cleared of the infection after a job to remove the cancerous material: in the case of the 23-month-old, a lung cancerous lump to take out, while the six-year-old had to have his left lung removed.
While it is impossible to know for sure how these boys developed the cancerous growths of the lungs, the researchers say they have identified the most likely cause.
In the case of the 23-year-old, his 35-year-old mother, who had not received the human papillomavirus (HPV) vaccine, was diagnosed with cervical cancer just three months after the child’s birth, after a negative test seven months earlier. Eventually, the tumors spread to her lungs, liver and bones, and she died.
However, analysis of the tumor from her cervical tumor and her son’s lung tumor revealed the appearance of a gene profile in the form of specific mutations and alleles, and the absence of the Y chromosome – indicating that the boy’s cancer had developed. directly from his mother.
Six-year-old tumors had the same genetic names for their mother’s mother’s breast cancer – first seen through a tumor found during pregnancy, but considered, unfortunately, wrong , to be stable. Her uterus was subsequently removed, along with her fallopian tubes and ovaries, but she died two years after surgery from the infection.
Based on all of the above – and that the tumors of both sons had the traces of the HPV genome – the researchers concluded that lung cancer in the children was caused by extravasation. cervical tumors from the mothers of the children.
“The peribronchial [relating to airways of the respiratory system] a pattern of tumor growth in both children suggested that the tumors would arise from the spread of mother-to-infant vagina through a desire of vaginal fluid contaminated with a tumor at birth, ”the team explains.
In most cases involving the spread of mother-to-fetus cancer, placental delivery of cancer cells tends to spread cancers to the brain, bones, liver and other tissues, causing into the lungs. Here, it was just the lungs – which gives a strong idea of how the disease could have been transmitted to the bodies of the boys themselves.
“In both of our patients, tumors were seen only in the lungs and were localized throughout the bronchi,” the authors write.
“Maternal tumor cells appear to have been present in the amniotic fluid, secretions, or blood from the cervix and were introduced by the infants at the time of vaginal delivery.”
While the chances of this route of cancerous diseases appear to be very limited for an individual family, the researchers confirm that inhibition by HPV vaccination would prevent this mode of transmission. from happening – a particularly important message in the Japanese context, which has a troubled history with HPV vaccines.
Further, the researchers suggest that cesarean section should be the recommended form of birth for mothers with a history of uterine cervical cancer.
Beyond these takeaways, these grim cases of medical malpractice are a rare example of what we have yet to learn about cancer – and the brutal pathways through which the disease seems to spread itself.
“It was interesting to me, personally,” Debbie Saslow, senior director of HPV-related cancers and women at the American Cancer Society, who was not involved in the study, told Health Day.
“I didn’t know this was possible.”
The results are reported in New England Journal of Medicine.