Among those who received intramuscular injection of vitamin K, the risk of cancer was 2 times higher.The same result was obtained in another study of the same authors.
That is, preventing 30-60 cases of hemorrhagic disease will result in 980 The fact that evolution has allowed the development of vitamin K deficiency in normal breast-fed infants, which leads to a small risk of hemorrhagic disease, has always seemed physiologically perverse. The most likely explanation for this phenomenon is that the noun It is possible that the relative deficiency of vitamin K in the critical phase of rapid growth can protect vulnerable tissues from mutagenesis.
The probability of bleeding in infants not belonging to the risk group is 1 per 10,000. Among those who received the injection, the probability of bleeding is 1 per million. In this study, cancer (mainly leukemia) was associated with intramuscular injection of vitamin K (OR=1.44, CI: 1.00-2.08) Children who were diagnosed before the 12-month-old age were excluded from the study. Several more studies were conducted that did not detect a correlation between injection and elevated risk of cancer In this study, there was no correlation between injection and oncological diseases in general, but a correlation was found with acute lymphoblastic leukemia up to 6-y/o (OR=1.79).
At the moment it is believed that there is no connection between vitamin K injection and cancer, but randomized studies have not been conducted and a small increase in risk can not be excluded.
Authors believe that injections should apply only to infants at risk.
The authors analyzed 6 studies on the relationship between vitamin K injection and cancer, and concluded that if one data is analyzed, there is no association between the risk of leukemia and injection, and if others, then there is a small association (OR=1.21, CI:1.02-1.44.) When one study was excluded from the analysis, the statistical significance disappeared (OR=1.16, CI: 0.97-1.39)). The authors conclude that although it is impossible to exclude small effects, there is no conclusive evidence that injection vitamin K is associated with leukemia.Experimental vitamin K deficiency and spontaneous metastases. 1977, Hilgard, Br J Cancer
In patients with cancer of mice, which reduced the level of vitamin K in the diet, there was significantly less metastasis than in mice in the control group.The metastasis was influenced by the level of vitamin K, rather than blood coagulation, since anticoagulants were not affected on the number of metastases.Observations on vitamin K deficiency in the fetus and newborn: has made by mistake? 1995, Israels, Semin Thromb Hemost
The fetus of mammals and bird embryos has a significantly lower level of vitamin K than adults, and it's unclear why a normal newborn enters the outside world in a state that requires immediate intervention. The question why even adults do not have excess vitamin K , also remains unanswered.
Benzopyrene is a carcinogen for mice. In mice on a diet with a low level of vitamin K, tumors after the administration of this drug developed much more slowly than in mice on a normal diet.
In mice injected with vitamin K in addition to benzapyrene, the tumors developed faster.
When mice were given only vitamin K, without benzapyrine, the tumors did not develop.
The authors suggest that a low level of vitamin K the fetus is a secondary defense mechanism against xenobiotics that pass through the placenta.
BCG vaccination is associated with a 27% reduction in the risk of leukemia.BCG vaccination and the subsequent development of cancer in humans. 1981, Kendrick, J Natl Cancer Inst
But if you look at all cancers, the BCG vaccination was associated with a 13% increase in the risk of cancer. More:   
After on the southern island of New Zealand ceased inoculated BCG, and on the northern island continued, mortality from non-Hodgkin's lymphoma on the northern island increased, and on the southern island decreased, although it was the same before. amb BCG against leukemia unreasonable.
Varicella in childhood is associated with a decrease in the risk of cancer by 34%. Having three common colds per year decreases the risk of cancer by 77%-82%. Viral gastroenteritis – by 57%. High frequency of infections decreases the risk of cancer by 53%. Measles, mumps and rubella also decrease the risk of cancer by 17%-39%, but the result was not statistically significant.
Two hundred cancer patients got intravenous injections of mumps virus (Urabe strain). The only side effect was a slight fever in half of the patients.
In 26 patients regression of the tumor was observed. In majority of the patients the pain was alleviated. In 30 out of 35 patients, the bleeding decreased or stopped. In 30 out of 41 patients, ascites and swelling decreased or disappeared.
All three of the previous studies were conducted in Japan, and the results were of no interest to anyone outside the country. Then, in 2016, the notorious Mayo Clinic decided to take samples of this virus from Japan and test them in vitro and on mice. It turned out that indeed, the virus has an anti-cancer effect.Febrile infectious childhood diseases in the history of cancer patients and matched controls. 1998, Albonico, Med Hypotheses
Rubella in childhood is associated with a 62% reduction in the risk of various cancers (not including breast cancer) and chickenpox by 38%. Measles and mumps are associated with a 10-15% reduction in cancer risk (but not statistically significant)
One or more children's febrile illnesses are associated with a 73% reduction in the risk of cancer.
Those who did not have measles in their childhood (or had a sick atypical, without a rash, like after vaccination) had an increased risk in adulthood: 1) immunoreactive diseases (autoimmune diseases due to an infectious disease),
2) skin diseases (dermatitis, eczema, etc.),
3) degenerative bone and cartilage disease (osteoarthritis, etc.),
4) oncological diseases.