PGR and breast cancer: Interestingly, among 58 BC cells whose SYT13 expression levels were available, ER-positive cells (n = 17) displayed significantly higher SYT13 mRNA levels than ER-negative ones (n = 41, p < 0.001; Figure 1b) and PgR-positive specimens (n = 9) also exhibited higher SYT13 mRNA expression levels than PgR-negative specimens (n = 49, p = 0.005; Figure 1b).