The researchers estimate that mother-to-child transmission of cancer occurs perhaps only twice in every million births in mothers with cancer, usually through the placenta.
But that’s not the only way a mother with cancer can unknowingly infect her child, scientists say .
In a new case study published by scientists from Japan, doctors report a rare case in medicine: vaginal transmission of cancer cells from mothers with cervical cancer to babies at birth.
” It is theoretically possible for a tumor to be transmitted to the birth canal from mother to child during vaginal delivery,” explains in their article researchers led by pediatric oncologist Ayumu Arakawa of the National Cancer Center Hospital in Tokyo.
” If the mother has cervical cancer, the baby may be exposed to tumor cells in the fluids of the birth canal and may receive tumor cells into the lungs.”
This obscure and previously unknown vector – supposedly inhaling cancer from the very first breath – is likely responsible for two otherwise unrelated cases of childhood lung cancer diagnosed in a pair of young male patients, 23 months old and six years old.
In both cases, patients were admitted to the hospital with symptoms of their illness: a 23-month-old child experienced a cough, and a six-year-old child experienced chest pain.
In each case, the computed tomography revealed what ended up being cancerous tumors in the boys’ lungs, which in both cases had been successfully treated, albeit for a long time.
Both young patients underwent repeated sessions of chemotherapy, but were cured of the disease only after operations to remove cancerous tissue: a 23-month-old patient had a malignant lobe of lung tissue removed, and a six-year-old boy required removal of the entire left lung.
While it’s impossible to know exactly how these boys developed lung cancers, the researchers say they’ve identified the most likely cause.
For the 23-month-old baby, her 35-year-old mother, who had not received the human papillomavirus ( HPV) vaccine , was diagnosed with cervical cancer just three months after the baby was born, having had seven negative results months earlier. Eventually, the tumor spread to her lungs, liver and bones, and she died.
However, tissue analysis of her cervical tumor and her son’s lung tumor revealed similar gene profiles in the form of certain mutations and alleles, as well as the absence of a Y chromosome, suggesting that the boy’s cancer originated directly from his mother.
The six-year-old’s tumors had the same genetic traits as his own mother’s cervical cancer, which was first discovered through a tumor that was discovered during her pregnancy but was unfortunately incorrectly considered stable. Later, her uterus, fallopian tubes and ovaries were removed, but she died two years after the operation from the disease.
Based on all of the above – and that both sons’ tumors also show signs of the HPV genome – the researchers concluded that the lung cancer in children was caused by the transmission of cervical tumors from the mothers of the children.
While the chances of this route of cancer infection seem incredibly small for any single family, the researchers emphasize that prevention through HPV vaccination will further prevent the spread of this mode of transmission – a particularly important message in the Japanese context.
In addition, the researchers suggest that caesarean section should be the recommended form of delivery for mothers with a history of cervical cancer.
Beyond these findings, these grim cases of an extremely rare medical phenomenon exemplify how much we still have to learn about cancer – and the treacherous pathways in which the disease spreads.
Previously, HB wrote that using an ancient evolutionary survival mechanism, cancer cells go into a state of sluggish, slow division in order to survive in the harsh conditions created by chemotherapy.
Dr. Catherine O’Brien and her team at Princess Margaret Cancer Hospital in Canada have found that all cancer cells have the ability to become defensive until the threat or chemotherapy is removed.
This is the first study to show that cancer cells launch an evolutionarily conserved program to survive chemotherapy. In addition, the researchers show that new therapeutic strategies targeting cancer cells in this condition can prevent cancer from regrowing.
“ The tumor acts as a whole organism, capable of going into a slow dividing state, conserving energy to help it survive,” says Dr. O’Brien, who is also an assistant professor of surgery at the University of Toronto.
