FGF2 and karyomegalic interstitial nephritis: Therefore, although primary cultures of fibroblasts from AK samples, independently from KIN grade, did not display relevant differences in terms of cell morphology and growth mode if compared to their perilesional counterpart, the significant increase in the FGF2 mRNA transcripts detected in the dermal portion of all AK lesions, compared to the corresponding perilesional controls, indicated an increased ability of all AK fibroblasts to release this growth factor.