Growing tumors evade anti-tumor immunity

The immunological pressure occurring during tumor progression might be harmful for the tumor to survive but the cancer cells evade the condition by restraining the anti-tumor immune response.

Cancerous tumors often grow so fast that they use up their available blood supply, creating a low-oxygen environment called hypoxia. Cells normally start to self-destruct under hypoxia, but in some tumors, the microenvironment surrounding hypoxic tumor tissue has been discovered to protect the tumor with the help of MicroRNA.

MicroRNAs are small, noncoding RNA molecules that regulate genes by silencing RNA, they have increasingly been implicated in tumor survival and progression. Researchers examined different types of tumor for altered levels of microRNAs. They identified two microRNAs ;miR25 and miR93 whose levels increased in hypoxic tumors.

The team then measured levels of those two microRNAs in the tumors of cancer patients and found that tumors with high levels of miR25 and miR93 led to a worse prognosis in patients compared to tumors with lower levels. The reverse was true for another molecule called cGAS: the lower the level of cGAS in a tumor, the worse the prognosis for the patient.
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