case_images: PMC11056527_01
case_images: MRI revealed a pelvic cystic mass (A); histological examination of the tumor demonstrated a clear cell morphology with papillary and focal solid growth patterns, consistent with the diagnosis of ovarian clear cell carcinoma (OCCC) (B); Genomic profiling of the tumor exhibited a somatic mutation pattern consistent with the OCCC. Germline mutations, including CHEK1, were detected in the peripheral blood specimen (highlighted in yellow) (C); and a timeline summarizing the key clinical events of the proband (D).
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case_images: Figure 1A ). Further serum examination showed elevated levels of tumor biomarkers: CA125 at 49.80 U/mL (normal range 0.1 ~35 U/ml) and HE4 at 3250 pmol/L (normal range <70 pmol/L for premenopause women and <140 pmol/L for post-menopause women). Hematoxylin and eosin (H&E) staining of formalin-fixed paraffin-embedded (FFPE) sections from the right ovarian appendage revealed a clear cell carcinoma with papillary and focal solid growth patterns ( Figure 1B ). This analysis revealed somatic mutations, including KRAS exon 2 c.35G>T p.G12V (26.7%), PPP2R1A exon 5 c.547C>T p.R183W (18.1%), and PIK3R1 exon 13 c.1721_1727del p.K575Efs*5 (21%) ( Figure 1C ). The timeline summarized the major clinical events of the patient ( Figure 1D ).
case_images: The family pedigree showed multiple members with cancer, including the proband with ovarian cancer at 57, the father with gastric cancer at 64, an uncle with a brain tumor at 72, the grandfather with esophageal cancer at 80, and the mother with renal cell carcinoma at 75. The CHEK1 c.613 + 2T>C mutation was confirmed in the proband, the father, and two siblings. Note that the mutation in the father was validated using NGS instead of Sanger sequencing due to poor sequencing results from the PCR product, likely attributed to low DNA quality from the very old tumor block.
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case_images: Unfortunately, no specimens were available to evaluate the mutation status of her deceased grandfather, who was diagnosed with esophageal cancer at the age of 80, and her uncle, who was diagnosed with a brain tumor at the age of 72 ( Figure 2 ).
case_images: RT-PCR analysis of peripheral blood from the proband revealed that the CHEK1 c.613 + 2T>C mutation caused a splicing error, resulting in the inclusion of a 20 bp intronic sequence in the CHEK1 transcript (A); an RNA NGS assay demonstrated a similar aberrant CHEK1 transcript due to the mutation at the splicing site (arrow) (B); and an ideogram illustrated the wild-type splicing donor and acceptor sites of CHEK1 intron 6, along with the alternative splicing donor and acceptor sites from the mutated allele. This alternative splicing event leads to the formation of a premature stop codon (C).
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case_images: Sanger sequencing of this PCR product confirmed that the CHEK1 c.613 + 2T>G mutation disrupted the donor splice site of exon 6, leading to the utilization of an alternative splice site located 20 bp downstream of exon 6 ( Figure 3A ). A similar aberrant CHEK1 transcript was confirmed by a RNAseq analysis ( Figure 3B ). E205Gfs*41) ( Figure 3C ).