PKD1 and breast lobular carcinoma: Investigation of other publicly available microarray datasets on the NCBI Gene Expression Omnibus (GEO) showed that PRKD1 is detected at appreciable levels in normal lobular and ductal breast cells [GEO:GDS2635] [45], in atypical hyperplasia [GEO:GDS1250] [46] and in the cancerous lesions invasive ductal and lobular carcinomas [GEO:GDS2635] [45], suggesting that PKD1 expression is indeed decreased with increased invasiveness of the tumours.