PARP1 and neoplasm: The following two examples further highlight the difficulty in identifying and discerning tumor-promoting and tumor-suppressing functions, even though targeting SHP2 in frank colon cancer may be beneficial: first, SHP2 appeared to worsen the activation of the interferon gene stimulatory factor (STING) pathway by limiting the DNA repair mediated by poly ADP-ribose-polymerase 1 (PARP1) in colorectal cancer cells, indicating that SHP2 agonist lovastatin combined with chemotherapy is a viable treatment option for colorectal cancer (112).