In the case of Ha-MSV-containing constructs stably integrated in the two human breast cancer lines, however, CAT expression was more than two orders of magnitude greater than that transiently expressed in these cells.
Although this result is currently a matter of controversy, further studies must be independently repeated to be conclusive; -- another RFLP was found in c-mos proto-oncogene, which is detected only in patients with breast cancers or other types of tumors.
The 5-kb allele of the MOS oncogene, previously proposed to be associated with breast cancer, was absent in these families, suggesting that polymorphism at this locus is not associated with inherited susceptibility.