Our results echo the recent description of a PTEN circular RNA, circPTEN1, acting as a tumor suppressor that is downregulated in the tumor tissues of colorectal cancer [30], as well as a previous RNA-seq study showing that circRNAs were globally reduced in tumor tissues from colorectal cancer patients, compared to matched normal tissues [31], suggesting a negative correlation of global circRNA abundance and proliferation. Here, PTEN is linked to neoplasm.