PRKCD and cancer: The enhancedelectron flux to cytochrome c from unbalanced PKCδ/retinoidmolecule signalosome increases spectacularly the Raman signal of thereduced cytochrome in cancer cells because the reduced cytochrome(Fe2+) has much higher intensity of the Raman bands thanthe oxidized cytochrome c (Fe3+). Consequently, the increase in Raman signal at1582 cm–1 upon incubation with retinoic acid demonstratesa conversion from oxidized cytochrome c to reducedcytochrome c.