GRM6 and breast cancer: Fresh-frozen human retinas (age range: 40–60; see Materials and methods for full description of samples) were then tested for isolation and profiling of human BC subtypes using a probe set for GRM6. This gene is expressed in cone ON bipolar cells and rod bipolar cells (RBC) in the mouse and human retina (Shekhar et al., 2016; Cowan et al., 2019) (Figure 2a).