CREB3L1 and breast cancer: Although luminal A breast cancers generally showed an increase in CREB3L1 expression, nearly one-quarter of this subtype (24%; 92/379) had CREB3L1 expression levels less than the median expression seen in normal breast tissue, though only 7% (26/379) showed reductions more than one standard deviation below the mean for normal breast tissue (i.e. Z score < -1) (S1 Table).