Finally, we compared the number of pathogenic variants in five genes that are frequently mutated in ovarian cancer BRCA1, BRCA2, KRAS, PIK3CA and TP53. This analysis highlighted that care should be taken in identifying pathogenic mutations using the state-of-the-art variant callers as their concordance in the number and type of mutations identified per gene and per tumour was very low. The gene discussed is PIK3CA; the disease is ovarian cancer.