No high score for p53 protein expression (i.e., positive staining of >20% of examined cells) was observed; lower scores were seen in 5 of 18 (28%) hepatocellular carcinomas, 1 of 9 (11%) cholangiocarcinomas, and 0 of 8 (0%) hepatic angiosarcomas.
These data indicate that p53 mutations are uncommon in sporadic hepatic angiosarcomas (2/21, 9%), and the mutational profile is consistent with endogenous mechanisms.
Amplification of MDM2 was not found, but in two of the angiosarcomas an A:T to T:A missense mutation was detected. p53 sequence analysis of vinyl chloride associated cancers may provide valuable information on the relationship between carcinogen exposure and DNA damage in cancer-related genes.
Herein, we report a patient with advanced angiosarcoma, who received apatinib at a daily dose of 250 to 725 mg, resulting in a partial response for three months, which may be related to Kinase Insert Domain Receptor (KDR) gene amplification.
Likewise, activating mutations in the receptor tyrosine kinase KDR (VEGFR2) have been reported in angiosarcomas and non-small cell lung cancers; the KDRA1065T mutation is reported to be sensitive to VEGFR kinase inhibitors, and fibroblast growth factor receptor inhibitors are in trials.
Together, these findings indicate that the PLCγ1-R707Q mutation causes constitutive activation of PLCγ1 and may represent an alternative way of activation of KDR/PLCγ1 signaling besides KDR activation in angiosarcomas, with implications for VEGF/KDR targeted therapies.
The genetic bases of these tumors have been partially revealed in recent studies reporting genetic alterations such as amplifications of MYC (primarily in radiation-associated angiosarcomas), inactivating mutations in PTPRB and R707Q hotspot mutations of PLCG1.
The genetic bases of these tumors have been partially revealed in recent studies reporting genetic alterations such as amplifications of MYC (primarily in radiation-associated angiosarcomas), inactivating mutations in PTPRB and R707Q hotspot mutations of PLCG1.