Quote:Researchers have reported that the SARS-CoV-2 mRNA-LNP vaccine may pose the risk of development and progression of cancer [25-28]. In addition, several case reports have described cancer developing or worsening after vaccination and discussed possible causal links between cancer and mRNA-LNP vaccination [29-34].



Based on the molecular weight of BNT162b2 mRNA (Pfizer-BioNTech), the mRNA content per dose is estimated at 13 trillion molecules and 40 trillion molecules in mRNA-1273 (Moderna) [35,36]. The total number of cells in humans is estimated to be 37.2 trillion [37], making the number of mRNA-LNPs very high, ranging from one-third to the equivalent of the total cell number. After inoculation, the mRNA-LNPs are delivered to various organs, especially the liver, spleen, adrenal gland, ovary, and bone marrow [38]. In one study, vaccine mRNA was detected in the lymph nodes of persons vaccinated with hybridization of a SARS-CoV-2 mRNA vaccine-specific probe 7 to 60 days after the second mRNA-1273 or BNT162b2 dose [39]. Modified mRNA with N1-methyl-pseudouridine could translate a large amount of SARS-CoV-2 spike protein (S-protein) [40]. S-protein emerged on the surface of exosomes in the blood of the vaccinated [41]. Fragments of vaccine-specific recombinant S-protein were found in blood specimens of 50% of vaccine recipients and were still detected three to six months later [42].


A study of more than 50,000 employees at a medical institution in the United States observed the incidence of the Omicron variant epidemic based on the number of vaccine doses received (0, 1, 2, 3, and 4 or more doses) over a period of 26 weeks and showed that the number of vaccines received was positively correlated with the cumulative incidence rate of COVID-19 [46]. Susceptibility to COVID-19 infection after multiple vaccinations may be enhanced by antibody-dependent enhancement [47], immune imprinting [39,48], and immunosuppression [25-27]. This can result in a risk of exposure to viral S-protein in addition to vaccine S-protein for the multiple-vaccinated. These data suggest a significant impact on vaccine recipients, including the large number of mRNA-LNPs that are injected, their rapid and widespread distribution particularly into specific organs, the amount of S-protein produced, its long persistence in the body, and increased susceptibility to infection. Next, we consider each factor that may contribute to the involvement of the mRNA-LNP SARS-CoV-2 vaccine in increasing mortality from all cancers and some specific cancer types.


The SARS-CoV-2 vaccine has been shown to cause immunosuppression and lead to the reactivation of latent viruses such as varicella-zoster virus (VZV, human herpesvirus 3; HHV3) or human herpesvirus 8 (HHV8) in some cases [75,76]. HHV8 is considered oncogenic and can cause Kaposi's sarcoma. Oropharyngeal cancer is reported to be caused by the Ebstein-Barr virus (EBV, HHV4) or human papillomavirus (HPV) [77], which also may be reactivated by possible immunosuppression resulting from vaccination. These phenomena could also help explain the excess deaths from lip/oral/pharyngeal cancer in 2022 when mass vaccination with third and later doses was underway.

Cancer development by SARS-CoV-2 mRNA vaccine
In our study, the AMRs of ovarian cancer, leukemia, prostate, lip/oral/pharyngeal, pancreatic, and breast cancers increased significantly beyond the predicted rates, especially in 2022. All of these cancers are known as estrogen and estrogen receptor alpha (ERα)-sensitive cancers [78-83]. Recent research by Solis et al. on the binding ability of S-protein of SARS-CoV-2 against over 9,000 human proteins has shown that S-protein specifically binds to ERα and upregulates the transcriptional activity of ERα. The addition of estradiol (E2) to human breast cancer cells causes proliferation of the cancer cells, whereas the addition of raloxifene, a selective ERα modulator, inhibits proliferation. Breast cancer cells grow when S is added instead of E2, and the addition of raloxifene inhibits their growth. Solis et al. also mentioned that the finding of S-ERα cytosolic colocalization may lead to a potentiation of membrane-bound ERα signaling [84]. Membrane-bound ERα has been implicated in many pathways, including the activation of c-Myc, which promotes the cell cycle and impacts cancer development [85].


ERα-mediated transcription may induce endogenous DNA double-strand breaks (DSBs) in ER-sensitive cancers [86]. Studies have shown that transcriptionally activated ERα induces DSBs by topoisomerase II and the recently known R-loop/G-quadruplex structures formation, significantly increasing the need for BRCA1 for their repair in breast cancer cells [87-89]. One study showed nuclear translocation of mRNA and S protein with the nuclear localization signal [90], and an in silico bioinformatic analysis showed interactions between the S2 subunit of S-protein and BRCA1, BRCA2, and P53 [91], possibly resulting in their sequestration and dysfunction. The possible co-occurrence of high BRCA1 demand to repair DNA damage caused by activated transcription via ERα bound with S-protein along with dysfunction of BRCA1 sequestrated by S-protein raises concerns about increased cancer risk in ERα-sensitive cells in mRNA-LNP SARS-CoV-2 vaccine recipients.


As mentioned above, there is also great concern about the risk of dysfunction in the crucial cancer suppressor genes, brca2 and P53, as well as BRCA1, through mechanisms involving downregulation of IRF9 through interference by specific miRNA in exosomes [26] and the possible sequestration by the S2 subunit of S-protein in the vaccine [91]. Impaired BRCA1 activity is associated with higher risk of breast, uterine, and ovarian cancer in women and prostate cancer in men, as well as moderately higher risk of pancreatic cancer in both men and women [92]. BRCA2-associated cancers include breast and ovarian cancer in women, prostate and breast cancer in men, and acute myeloid leukemia in children [26]. These findings are highly consistent with our results. 


Additional factors that may contribute to the development of cancer are being investigated. Since endogenous ROS causes oxidative DNA damage [93], excessive oxidative stress resulting from the downregulation of ACE2 by S-protein [57] may contribute to cancer development. One study showed that the downregulation of the Mas receptor promotes the metastasis of epithelial ovarian cancer [94]. ACE2 receptor, bound by S-protein after mRNA-LNP vaccination, may directly cause downregulation and subsequent dysfunction of the Mas receptor, possibly leading to an increased risk of metastasis in vaccinated women with ovarian cancer. The observation that injected LNPs accumulate particularly in the ovaries and bone marrow [38] could better explain our findings of excess mortalities from ovarian cancer and leukemia in 2022. According to an analysis of scientific literature about sex hormone receptors in head and neck squamous cell carcinoma (HNSCC), ERα plays various roles in the biopathology of HNSCC, particularly oropharyngeal cancer. These include promoting DNA hypermutation, facilitating HPV integration, and cooperating with epithelial growth factor receptor (EGFR) [82]. This may explain the increased mortality of lip/oral/pharyngeal cancer in our study.


A recent study showed that SARS-CoV-2 RNA could be reverse-transcribed to DNA and integrated into the human cell genome in vitro [95]. Another study reported that transfected mRNA in the human cells exposed to BNT162b2 leads to unsilencing of the endogenous retrotransposon long interspersed element-1 (LINE-1) and reverse transcription of vaccine mRNA sequences to DNA in the nucleus [96]. Accumulation of vaccine mRNA and reverse-transcribed DNA molecules in the cytoplasm could be expected to induce chronic autoinflammation, autoimmunity, DNA damage, and cancer risk in susceptible individuals [97].


The U.S. Food and Drug Administration (FDA) states in its guidance for the production of viral vaccines for infectious disease, "There are several potential mechanisms by which residual DNA could be oncogenic, including the integration and expression of encoded oncogenes or insertional mutagenesis following DNA integration" [98]. The FDA's guidelines are essential for Japan because Japan's special emergency use authorization depended on FDA approval during the COVID-19 pandemic [99]. Recently, some researchers have reported that several lots of Pfizer-BioNTech and Moderna vaccines contain a certain amount of double-stranded DNA fragments from residual plasmid vectors [100,101]. Some of them mentioned that the amount of residual DNA exceeds the regulatory limits for residual DNA set by the FDA. Given these reports and the FDA's regulatory statement, further investigation is required to determine whether the observed excess cancer deaths following mass vaccination were linked to reported residual DNA in the vaccine.

Conclusions

Statistically significant increases in age-adjusted mortality rates of all cancer and some specific types of cancer, namely, ovarian cancer, leukemia, prostate, lip/oral/pharyngeal, pancreatic, and breast cancers, were observed in 2022 after two-thirds of the Japanese population had received the third or later dose of SARS-CoV-2 mRNA-LNP vaccine. These particularly marked increases in mortality rates of these ERα-sensitive cancers may be attributable to several mechanisms of the mRNA-LNP vaccination rather than COVID-19 infection itself or reduced cancer care due to the lockdown. The significance of this possibility warrants further studies. This article was previously posted to the Zenodo repository server on September 18, 2023.