The MCF-7 human breast cancer cell line responds to estrogen stimulation in vitro by increased secretion of growth factors and proliferation and in vivo by tumor formation in the nude mouse. To test a possible role of growth factor secretion in expression of the tumorigenic phenotype, we stably transfected MCF-7 cells with the v-Ha-ras oncogene to produce the MCF-7ras cell line. The MCF-7ras cell line was tumorigenic in the absence of estrogens and secreted 3- to 5-fold elevated levels of a high molecular weight form of a type alpha transforming growth factor-like growth factor, type beta transforming growth factor, and insulin-like growth factor I. MCF-7ras cells, in contrast to MCF-7, were less sensitive to further growth stimulation by estrogen, type alpha transforming growth factor, and insulin-like growth factor I and showed little change in receptor levels for these hormones. Conditioned medium from MCF-7ras cells as well as two of its component growth factors (insulin-like growth factor I and type alpha transforming growth factor) replaced estrogen in stimulating MCF-7 colony formation in vitro. A coordinate increase in growth factor secretion by human breast cancer may contribute to its escape from estrogen dependence.
This research output has an Altmetric Attention Score of 12. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 13 October 2020.
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#3,834,170
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Outputs from Proceedings of the National Academy of Sciences of the United States of America
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#1,612
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Outputs of similar age from Proceedings of the National Academy of Sciences of the United States of America
#10
of 197 outputs
Altmetric has tracked 34,763,505 research outputs across all sources so far. Compared to these this one has done well and is in the 88th percentile: it's in the top 25% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 119,650 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 40.2. This one has gotten more attention than average, scoring higher than 64% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 61,544 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 96% of its contemporaries.
We're also able to compare this research output to 197 others from the same source and published within six weeks on either side of this one. This one has done well, scoring higher than 88% of its contemporaries.
