In contrast to previous observations, however, we found that Hs578T, a breast cancer cell line with relatively high PHGDH protein expression levels, but without a genomic amplification of PHGDH, was insensitive to PHGDH knockdown, as was the non-amplified and low-expressing MDA-MB-231 [4]. The gene discussed is PHGDH; the disease is breast carcinoma.