CDA and neoplasm: The 5′R/5′S ratio of cdA was found to be higher than the ratio of corresponding cdG in all groups of samples, as shown in Figure 4C. A decrease in the R/S ratio of cdG and a significant diminution of the R/S ratio of cdA (p = 0.0211) were noted in 17-week-old tumor-bearing mice, compared with younger xenograted animals (Tables S5 and S6).