I need to analyse the mRNA splice variant called ARV-7 from the Metastatic Prostate Cancer, SU2C/PCF Dream Team (Robinson et al., Cell 2015) data in cbioportal.org. The downloaded data looks like this

SampleID    AR
1115153 3.0771
1115154 1.4149
1115156 0.5581
1115157 0.5911
1115161 1.4255
1115183 -0.1321
1115202 3.9562
1115244 -0.5652

How can I find the samples with the ARV-7 splice using an R package or using cbioportal