The vaccines may cause cancer to grow.

“Kariko, et al., demonstrated that RNA recognition by Toll-like receptors (TLRs) is suppressed via modification of the nucleosides in mRNA molecules.”

mRNA vaccines for COVID-19: what, why and how 

And

“The ability of these receptors in distinguishing “self” and “non-self” antigens is a cornerstone in the innate immunity system; however, misregulation links inflammatory responses to the development of human cancers. It has been known for some time that aberrant expression and regulation of TLRs not only endows cancer cells an opportunity to escape from the immune system but also supports them through enhancing proliferation and angiogenesis.”

Toll-like receptors (TLRs) in cancer; with an extensive focus on TLR agonists and antagonists 

More about the Toll-like receptors: Pattern recognition receptors (PRRs): toll-like receptors

The Pfizer vaccine reduced the response of certain toll-like receptors (which are necessary to detect and fight cancer within the body):

“The response of innate immune cells to TLR4 and TLR7/8 ligands was lower after BNT162b2 vaccination, while fungi-induced cytokine responses were stronger. In conclusion, the mRNA BNT162b2 vaccine induces complex functional reprogramming of innate immune responses, which should be considered in the development and use of this new class of vaccines.”

The BNT162b2 mRNA vaccine against SARS-CoV-2 reprograms both adaptive and innate immune responses

“T-cell exhaustion is evidently the main mechanism underlying immune dysfunction during chronic viral infection and cancer.”

Activation or exhaustion of CD8+ T cells in patients with COVID-19

At the very least, the COVID vaccines are causing an increase in cancer markers: