Ulf Gyllensten

Detecting TP53 mutations in paired liquid and tissue biopsies from patients with high‐grade serous ovarian carcinoma

Abstract High‐grade serous ovarian carcinoma (HGSC) is the most lethal form of ovarian carcinoma, often diagnosed at advanced stages due to non‐specific symptoms and the lack of reliable screening methods. This proof‐of‐concept study aimed to develop a robust TP53 mutation panel for detecting HGSC through targeted DNA sequencing in both liquid and solid biopsies. We constructed a custom TP53 gene panel and utilized a PCR‐based unique molecular identifier approach for next‐generation sequencing to analyze 94 samples from 11 patients diagnosed with HGSC, including primary tumor, plasma, ascites, ovarian cyst fluid, vaginal, endocervical and endometrial samples. Detected TP53 mutations were analyzed, categorized, and their frequencies calculated. Pathogenic TP53 mutations were identified in all patients, with 91% of the patients exhibiting one unique paired mutation across three or more sample types. The panel demonstrated high sensitivity and technical reproducibility, successfully detecting TP53 mutations across all sample types, with as little as 2.6 ng of DNA. TP53 mutations were consistently found in ascites, ovarian cyst fluid, and plasma samples, confirming the presence of pathogenic mutations in each sample type across all patients. This study underscores the potential of liquid biopsies in clinical molecular diagnostics. The TP53 mutation panel presented in this proof‐of‐concept study offers a promising approach for differential diagnostics and detection of HGSC, informative data prior to extended investigation and first‐line treatment guidance.

Temporal changes in the vaginal microbiota in self-samples and its association with persistent HPV16 infection and CIN2+

Abstract Background The vaginal microbiota has been reported to be associated with HPV infection and cervical cancer. This study was performed to compare the vaginal microbiota at two timepoints in women performing self-sampling and had a persistent or transient HPV16 infection. The women were tested for 12 high-risk HPV (hrHPV) types but only women with single type (HPV16) were included to reduce confounding variables. Methods In total 96 women were included in this study. Of these, 26 were single positive for HPV16 in the baseline test and HPV negative in the follow-up test and 38 were single positive for HPV16 in both tests and diagnosed with CIN2+ in histology. In addition, 32 women that were negative for all 12 HPV tested were included. The samples of vaginal fluid were analyzed with the Ion 16S™ Metagenomics Kit and Ion 16S™ metagenomics module within the Ion Reporter™ software. Results K-means clustering resulted in two Lactobacillus-dominated groups, one with Lactobacillus sp. and the other specifically with Lactobacillus iners. The two remaining clusters were dominated by a mixed non-Lactobacillus microbiota. HPV negative women had lower prevalence (28%) of the non-Lactobacill dominant cluster in the baseline test, as compared to women with HPV16 infection (42%) (p value = 0.0173). Transition between clusters were more frequent in women with persistent HPV16 infection (34%) as compared in women who cleared the HPV16 infection (19%) (p value = 0.036). Conclusions The vaginal microbiota showed a higher rate of transitioning between bacterial profiles in women with persistent HPV16 infection as compared to women with transient infection. This indicate an instability in the microenvironment in women with persistent HPV infection and development of CIN2+.