A single biomarker may not yield a reliable binary clinical answer: B cell lymphoma 6 testing and resulting...

To study the associations of B cell lymphoma 6 (BCL6) in endometrial endometriosis, and to determine a practice's experience testing BCL6 in patients with recurrent pregnancy loss/recurrent implantation failure (RPL/RIF).

Retrospective chart review.

Endometrial samples were collected at the time of laparoscopy from 19 reproductive-aged individuals with known stage II-IV endometriosis. Endometrium biopsies were also collected from eight healthy controls, at a single academic center.

Results using standard immunohistochemical staining for BCL6 on endometrial biopsies from October 2019 to March 2023 were obtained. For the in vitro fertilization patients with a positive BCL6 result (HSCORE≥1.4), postbiopsy interventions on the basis of the positive result were then compared with positive patients who did not receive treatment for their positive result of BCL6 test.

Outcomes for the embryo transfer cycle immediately after that biopsy/intervention were analyzed. Descriptive statistics with independent t-tests for continuous data, and χ² or Fischer's exact tests for categorical data were used. A two-sided P value of <.05 was considered statistically significant.

We found no significant upregulation of BCL6 or downstream target gene expression changes in endometriosis relative to the control group, indicating no significant single-cell differences in the BCL6 endometriosis pathway among endometrial samples from these patients with known endometriosis. A total of 33 RPL/RIF patients were treated on the basis of a positive result vs. those who were not treated. These two groups also did not have any statistically significant differences in their age, body mass index, history of live births, previous pregnancy losses, or HSCOREs. Of the patients treated for their positive BCL6 results, 20 (86%) were treated with leuprolide acetate, 9 (39%) with an aromatase inhibitor, and 1 (4%) was surgically managed with a laparoscopy in preparation for their frozen embryo transfer. There were no differences in implantation rate, miscarriage rate, or ongoing pregnancy rate among the patients who were and were not treated for their positive BCL6 result.

The relationship between BCL6 and endometriosis may not be the golden solution to a single marker focus for testing, or for subsequent therapy planning among infertility patients. Clinicians should be cautious in using single marker testing for diagnosing and treating endometriosis in patients without strong additional therapeutic evidence.