Various repair events following CRISPR/Cas9-based mutational correction of an infertility-related mutation in mouse embryos

PURPOSE

Unpredictable genetic modifications and chromosomal aberrations following CRISPR/Cas9 administration hamper the efficacy of germline editing. Repair events triggered by double-strand DNA breaks (DSBs) besides non-homologous end joining and repair template-driven homology-directed repair have been insufficiently investigated in mouse. In this work, we are the first to investigate the precise repair mechanisms triggered by parental-specific DSB induction in mouse for paternal mutational correction in the context of an infertility-related mutation.

METHODS

We aimed to correct a paternal 22-nucleotide deletion in Plcz1, associated with lack of fertilisation in vitro, by administrating CRISPR/Cas9 components during intracytoplasmic injection of Plcz1-null sperm in wild-type oocytes combined with assisted oocyte activation. Through targeted next-generation sequencing, 77 injected embryos and 26 blastomeres from seven injected embryos were investigated. In addition, low-pass whole genome sequencing was successfully performed on 17 injected embryo samples.

RESULTS

Repair mechanisms induced by two different CRISPR/Cas9 guide RNA (gRNA) designs were investigated. In 13.73% (7/51; gRNA 1) and 19.05% (4/21; gRNA 2) of the targeted embryos, only the wild-type allele was observed, of which the majority (85.71%; 6/7) showed integrity of the targeted chromosome. Remarkably, for both designs, only in one of these embryos (1/7; gRNA 1 and 1/4; gRNA2) could repair template use be detected. This suggests that alternative repair events have occurred. Next, various genetic events within the same embryo were detected after single-cell analysis of four embryos.

CONCLUSION

Our results suggest the occurrence of mosaicism and complex repair events after CRISPR/Cas9 DSB induction where chromosomal integrity is predominantly contained.

Cervical cancer screening and outcomes for women under 25 years of age in Belgium: a 10-year nationwide study

OBJECTIVE

The aim of the study was to describe trends in cervical cancer screening and outcomes for women under 25 years of age in Belgium between 2010 and 2019 in response to a changed reimbursement policy.

MATERIALS AND METHODS

We used the databases of the National Health Insurance Institute (RIZIV/INAMI) and the Belgian Cancer Registry (BCR) for a nationwide description of cervical screening, subsequent diagnostic procedures and outcomes for women younger than 20 years and women aged 20-25 years between 2010 and 2019.

RESULTS

Over a 10-year period, the number of cytology screening tests and annual screening rates in women younger than 25 years have been reduced by 50%, but no increases in invasive cervical cancer or high-grade intraepithelial lesion diagnoses were observed. The major determinant of this decreased overscreening has been the limitation of reimbursement in 2013 to once every 3 years instead of once every 2 years. In women aged 25-29 years, there is no increase in invasive cervical cancer diagnoses after decreased screening of women younger than 25 years. To detect 29 invasive cervical cancers in women younger than 25 during the 10-year study period, a total of 5606 conizations were performed and 43 million EUR of Belgian health insurance budget was spent. Since the cost of hospitalization, sickness leave and negative psychological impact were not included in our estimation, these costs are underestimated.

CONCLUSION

Incidence of cervical cancer in women under 25 years remains low and screening is not effective in preventing cervical cancer, although there is clear evidence of potential reproductive harm and financial cost. We state that restricting reimbursement of cervical cancer screening before the age of 25 will improve guideline adherence and decrease healthcare expenditures without negatively impacting the health of the population.

Misdiagnosis of sebaceous carcinoma

BACKGROUND

Sebaceous carcinoma is an aggressive malignant tumour. To prevent mutilating surgery and improve patient outcomes, early diagnosis and prompt treatment are necessary. When the tumour invades surrounding tissues, treatment may become complex.

METHODS

We present a case report illustrating complex resection and reconstruction of a sebaceous carcinoma after initial misdiagnosis.

RESULTS

A 74-year-old man with a sebaceous carcinoma to his right upper eyelid had a delay in treatment due to initial misdiagnosis. Upon the correct diagnosis, computed tomography scan showed tumour invasion of the medial rectus muscle and tumour spread to the right parotid gland. An orbital exenteration, partial parotidectomy and selective cervical lymphadenectomy were performed. Frozen section examination showed false-free margins, as additional paraffin embedded sections showed uncomplete tumour resection. Adjuvant radiotherapy was offered to the patient. The treatment was complicated by radio necrosis, necessitating surgical reconstruction by a paramedian forehead flap. Final reconstruction of the right orbit was accomplished by a personalised epithesis.

CONCLUSIONS

Sebaceous carcinoma is a tumour that is often misdiagnosed. The aim of this case report is to emphasize the possible consequences of its misdiagnosis. An overview of characteristic clinical findings is provided to help reduce the number of misdiagnoses.

Case Report: An Unusual Course of Angiosarcoma After Lung Transplantation

A 35-year-old woman underwent bilateral lung transplantation for primary ciliary dyskinesia and developed vascular tumors over a slow time course. Initial presentation of non-specific vascular tumors in the lungs and liver for up to 6 years after transplantation evolved toward bilateral ovarian angiosarcoma. Tumor analysis by haplotyping and human leukocyte antigen typing showed mixed donor chimerism, proving donor origin of the tumoral lesions. In retrospect, the donor became brain dead following neurosurgical complications for a previously biopsy-proven cerebral hemangioma, which is believed to have been a precursor lesion of the vascular malignancy in the recipient. Donor-transmitted tumors should always be suspected in solid organ transplant recipients in case of uncommon disease course or histology, and proper tissue-based diagnosis using sensitive techniques should be pursued.

Pitfalls in assessing stromal tumor infiltrating lymphocytes (sTILs) in breast cancer

Stromal tumor-infiltrating lymphocytes (sTILs) are important prognostic and predictive biomarkers in triple-negative (TNBC) and HER2-positive breast cancer. Incorporating sTILs into clinical practice necessitates reproducible assessment. Previously developed standardized scoring guidelines have been widely embraced by the clinical and research communities. We evaluated sources of variability in sTIL assessment by pathologists in three previous sTIL ring studies. We identify common challenges and evaluate impact of discrepancies on outcome estimates in early TNBC using a newly-developed prognostic tool. Discordant sTIL assessment is driven by heterogeneity in lymphocyte distribution. Additional factors include: technical slide-related issues; scoring outside the tumor boundary; tumors with minimal assessable stroma; including lymphocytes associated with other structures; and including other inflammatory cells. Small variations in sTIL assessment modestly alter risk estimation in early TNBC but have the potential to affect treatment selection if cutpoints are employed. Scoring and averaging multiple areas, as well as use of reference images, improve consistency of sTIL evaluation. Moreover, to assist in avoiding the pitfalls identified in this analysis, we developed an educational resource available at www.tilsinbreastcancer.org/pitfalls.

Laparoscopic repair of post-abdominoperineal resection hernia: biological mesh and augmentation technique

Perineal hernias are infrequent complications following abdominoperineal surgeries. These hernias require surgical repair when they become symptomatic by several conventional or reconstructive techniques. The benefits of a full laparoscopic approach and/or the combined approach of a perineal repair of the pelvic floor associated to the laparoscopic placement of a traditional synthetic mesh have been previously demonstrated. In this article, we present the case of a perineal incisional hernia, post-abdominoperineal resection of the rectum after radio chemotherapy, in the neoadjuvant treatment of a rectal adenocarcinoma tumor. An alternative approach, not previously described for the surgical repair of this type of hernia, is presented to assess the feasibility of the suturing repair, and efficacy of a biological acellular porcine collagen implant Permacol(®). A full laparoscopic suturing for the closure of the perineal defect associated to biological mesh reinforcement was successfully undertaken, with good short-term outcomes.

An unusual complication after Roux-en-Y gastric bypass: torsion and infarction of the divided Omentum

A 41-year-old male was admitted from the emergency department with severe epigastric and right hypochondric abdominal pain. The patient had a laparoscopic Roux-en-Y gastric bypass operation 12 months previously. An abdominal computed tomography scan showed signs of omental infarction. A laparoscopy was performed and showed a torsion and infarction of the divided greater omentum. Resection of the ischemic omentum was performed.

Placenta percreta causing rupture of an unscarred uterus at the end of the first trimester of pregnancy: Case report

Reports on placenta percreta in early pregnancy leading to a spontaneous rupture of the uterus are rare. We report a case of this potentially life-threatening complication in the 14th week of pregnancy in an otherwise healthy woman who underwent a manual extraction of the placenta during a previous delivery but who had no history of severe pathology that could have potentially resulted in uterine damage. The occurrence of severe abdominal pain and the presence of a large quantity of free fluid in the abdomen necessitated an emergency laparotomy, revealing a haemoperitoneum due to rupture of the uterus, which was followed by a hysterectomy. This case demonstrates that in patients with a history of placenta accreta and subsequent manual extraction of the placenta, a close investigation of the uterine wall and placentation should be performed in the first trimester in order to anticipate a placenta percreta.