The tradeoff between cost and efficiency is omnipresent in organisms. Specifically, how the evolutionary force shapes the tradeoff between biosynthetic cost and translation efficiency remains unclear. In the cancer community, whether the adjustment of cost-efficiency tradeoff acts as a strategy to facilitate tumor proliferation and contributes to oncogenesis is uninvestigated. To address this issue, we retrieved the gene expression profile in various cancer types and the matched normal samples from The Cancer Genome Atlas (TCGA). We found that the highly expressed genes in cancers generally have higher tAI/nitro ratios than those in normal samples. This is possibly caused by the higher tAI/nitro ratios observed in oncogenes than tumor suppressor genes (TSG). Furthermore, in the cancer samples, derived mutations in oncogenes usually lead to higher tAI/nitro ratios, while those mutations in TSG lead to lower tAI/nitro. For a special case of kidney cancer, we investigated several crucial genes in tumor samples versus normal samples, and discovered that the changes in tAI/nitro ratios are correlated with the changes in translation level. Our study for the first time revealed the optimization of cost-efficiency tradeoff in cancers. The cost-efficiency dilemma is optimized by the tumor cells, and is possibly beneficial for the translation and production of oncogenes, and eventually contributes to proliferation and oncogenesis. Our findings could provide novel perspectives in depicting the cancer genomes and might help unravel the cancer evolution.