Figure 1.

Occurrence of M41 mRNA in human breast tumour cell lines. Total RNAs were isolated from the SV40-immortalised normal human mammary cell line, Huma 7 (lane 1), an elongated converted cell line, Huma 109 (lane 2) derived from the benign mammary tumour-derived cell line Huma 123 (lane 3), the malignant mammary epithelial cell lines MCF-7 (lane 4), T47-D (lane 5), ZR-75 (lane 6) and MDA-MB-231 (lane 7). These RNAs were subjected to Northern hybridisation as described in Materials and Methods, using a ³²P-labelled probe to M41 mRNA (A) or to ribosomal phosphoprotein, 36B4, mRNA (B) to check for the loading of RNA onto the gel. The arrows point to three bands of hybridisation in the three oestrogen receptor positive human breast cancer cell lines.