To analyze the impact of SDHx cancer-associated homozygous mutations on the expression of HIF-1α and miR-210, we used two PGL-derived cell lines, one composed of tumor cells which had been obtained from a tympanic PGL with homozygous SDHC exon 2 deletion (SDHC-PGL) [16] and other composed of tumor-associated fibroblasts which were derived from a SDHD-mutated (c.88_314+247del, p.His30Asn fs*11) jugular PGL (SDHD-TAFs). The gene discussed is HIF1A; the disease is neoplasm.