NRG4 and breast carcinoma: Furthermore, in breast cancer cells, NRG-2β was shown to promote telomere shortening, inducing chromosomal instability.[91] NRG-1β expression in breast cancer stromal cells correlated with a worse prognosis.[92] Also, NRG-2β and NRG-4 correlated with high-grade tumors.[93] On the other hand, in a cohort of 115 breast cancer patients, NRG-1α expression was present in 84% of samples and correlated with a better prognosis.[94] NRG-3 nuclear staining also correlated with low-grade tumors.[92]