In summary, this large-scale hospital-based case-control study revealed that two functional variants in the regulatory regions of the MTR gene, rs28372871 T > G and rs1131450 G > A, were associated with a significantly increased risk of PCa by reducing MTR expression, elevating homocysteine and SAH levels, reducing methionine and SAM levels, increasing the SAH/SAM ratio, and promoting invasion by PCa cells. The gene discussed is MTR; the disease is posterior cortical atrophy.