Optimizing Diagnostic Accuracy of Fine Needle Aspiration Biopsy Calcitonin Measurements in Detecting Medullary Thyroid Carcinoma

Background: The optimal cutoff value of calcitonin (Ctn) levels measured using an electrochemiluminescence immunoassay (ECLIA) obtained from the washout fluid of fine needle aspiration (FNA-Ctn) for the diagnosis of medullary thyroid carcinoma (MTC) is currently not established. We evaluated the diagnostic accuracy and clinical utility of FNA-Ctn for the diagnosis and location of MTC in patients with nodular or multinodular goiters. Methods: This was a case-control study nested on a prospective multicenter cohort of patients with nodular or multinodular goiter, normal or elevated serum Ctn, and thyroidectomy indications. Ctn and FNA-Ctn were measured using ECLIA methodology before surgery. From this nested cohort, MTC cases and controls (non-medullary pathology) were identified from the final pathological analysis. Cumulative incidence sampling of controls was randomly performed at a ratio of 1:2. Sensitivity, specificity, and area under the receiver operator curve (AUROC) were calculated for patients and the total number of thyroid nodules. Results: From 1272 patients included in the prospective cohort, 50 MTC cases and 105 controls were included. In this study, 286 thyroid nodules were evaluated (63 MTC and 223 non-MTCs). The median serum Ctn value was significantly higher in cases (525 pg/mL [interquartile range (IQR), 162.5-1.200]) than in controls (1.6 pg/mL [IQR, 0.5-5.6]; p < 0.001). The median FNA-Ctn value was significantly higher in MTC nodules (3.100 pg/mL [IQR, 450-45,200]) than in non-MTC nodules (0.5 pg/mL [IQR, 0.5-0.5]; p < 0.0001). In 11 MTC patients with multinodular goiter, the FNA-Ctn value was significantly higher in non-medullary nodules located in the same lobe where an MTC nodule was diagnosed (p = 0.0002). Overall, the FNA-Ctn AUROC was 0.99 [95% confidence interval, 0.98-1.0], and a threshold of ≥220 pg/mL showed 100% sensitivity and 98% specificity for MTC diagnosis. Conclusions: The use of FNA-Ctn measured by ECLIA showed adequate diagnostic accuracy for MTC diagnosis. Moreover, it may be clinically useful for localization in multinodular goiter when lobectomy is considered. Clinical Trial Registration: Clinicaltrials.gov NCT06067594.

Abstract 3994: Differential regulation of hormone receptors and Ki67 in luminal breast carcinomas and tumor-adjacent mammary glands by mifepristone treatment

Since antiprogestins inhibit the growth of preclinical mammary tumor models expressing higher levels of progesterone receptor (PR) isoform A (PRA) than isoform B (PRB), we designed a window-of-opportunity trial (MIPRA; NCT02651844) to study the benefits of mifepristone (MFP) in luminal breast carcinomas from postmenopausal patients selected by their PR+ expression (&gt;50%) and their PR isoform ratio (PRA/PRB&gt;1.5; PRA-H). A decrease in the cell proliferation marker Ki67 was registered after treatment in 14 out of the 20 tumors evaluated. This inhibition was associated with a decrease in PR, estrogen receptor (ER) and pSer118ER evaluated by immunohistochemistry while no changes in pSer167ER expression were observed (PMID: 36269797). In selected tissues from these samples we observed that the staining intensity in trapped glands within the MFP-treated tumors did not follow a similar trend as that of tumor cells. Thus, the aim of this study was to evaluate the expression of hormone receptors and Ki67 in non-neoplastic human mammary glands (nnMG) adjacent to the PRA-H tumor tissue of postmenopausal patients, treated (n=8) or not (n=9) with MFP. No differences in PR, ER and pSer118ER expression were observed between MFP-treated nnMG and those from untreated patients. Notably, contrarily to what occurred in tumors, there was a significant decrease of pSer167ER expression (p=0.008) in the MFP-treated nnMG compared to the untreated glands, suggesting a selective modulation in the AKT-mediated activation of ER. Regarding the proliferative state of the nnMGs, there was a slight but significant increase (p=0.02) in Ki67 expression in MFP-treated vs. non-treated nnMG. Data regarding the effect of antiprogestins in normal mammary glands is limited and points, in premenopausal women, to a decrease in the Ki67 index after treatment. The basal quiescent status of nnMG in postmenopausal women may explain this slight stimulatory effect. In conclusion, our results show that MFP exerts a specific regulatory effect in PRA-H tumors that is not observed in the nnMG, probably due to the fact that nnMG have presumably equimolar levels of PRA and PRB. In addition, to counteract the possible stimulatory effect that MFP may induce on nnMG, the combination of MFP and tamoxifen treatment is suggested.

Citation Format: Leo Saldain, Silvia Vanzulli, Paula Martinez Vazquez, Javier Burruchaga, Eunice Spengler, Claudia Lanari, Paola Rojas. Differential regulation of hormone receptors and Ki67 in luminal breast carcinomas and tumor-adjacent mammary glands by mifepristone treatment. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3994.

Beneficial Effects of Mifepristone Treatment in Patients with Breast Cancer Selected by the Progesterone Receptor Isoform Ratio: Results from the MIPRA Trial

PURPOSE

Preclinical data suggest that antiprogestins inhibit the growth of luminal breast carcinomas that express higher levels of progesterone receptor isoform A (PRA) than isoform B (PRB). Thus, we designed a presurgical window of opportunity trial to determine the therapeutic effects of mifepristone in patients with breast cancer, based on their high PRA/PRB isoform ratio (MIPRA; NCT02651844).

PATIENTS AND METHODS

Twenty patients with luminal breast carcinomas with PRA/PRB > 1.5 (determined by Western blots), and PR ≥ 50%, naïve from previous treatment, were included for mifepristone treatment (200 mg/day orally; 14 days). Core needle biopsies and surgical samples were formalin fixed for IHC studies, while others were snap-frozen to perform RNA sequencing (RNA-seq), proteomics, and/or Western blot studies. Plasma mifepristone levels were determined using mass spectrometry. The primary endpoint was the comparison of Ki67 expression pretreatment and posttreatment.

RESULTS

A 49.62% decrease in Ki67 staining was observed in all surgical specimens compared with baseline (P = 0.0003). Using the prespecified response parameter (30% relative reduction), we identified 14 of 20 responders. Mifepristone induced an increase in tumor-infiltrating lymphocytes; a decrease in hormone receptor and pSer118ER expression; and an increase in calregulin, p21, p15, and activated caspase 3 expression. RNA-seq and proteomic studies identified downregulated pathways related to cell proliferation and upregulated pathways related to immune bioprocesses and extracellular matrix remodeling.

CONCLUSIONS

Our results support the use of mifepristone in patients with luminal breast cancer with high PRA/PRB ratios. The combined effects of mifepristone and estrogen receptor modulators warrant clinical evaluation to improve endocrine treatment responsiveness in these patients. See related commentary by Ronchi and Brisken, p. 833.

Abstract P5-16-09: Transcriptome modulation by mifepristone treatment in breast cancer patients with higher levels of progesterone receptor A than B

Background: Preclinical data suggests that antiprogestins inhibit the growth of luminal breast carcinomas expressing higher levels of progesterone receptor isoform A (PRA) than isoform B (PRB). Thus, we designed a pre-surgical window of opportunity trial to determine the therapeutic effects of oral mifepristone (MFP) in 20 breast cancer patients selected by their high PRA/PRB isoform ratio (MIPRA; NCT02651844).Methods. MIPRA is an open-label, one-arm, prospective interventional study. After the selection process, 20 patients that met the inclusion criteria, with ER+, PRA/PRB&gt;1.5 determined by Western blots, and total PR ≥50% determined by immunohistochemistry (IHC), were included for daily MFP treatment (200 mg/day p.o., 14 days). Core needle biopsies and surgical samples were formalin-fixed for IHC studies, and others were snap-frozen for further molecular studies. Besides, plasma samples were obtained for MFP dosing by LC-MS/MS. RNA was extracted from frozen tissue with a column-based method. The library for sequencing was constructed using SMART-Seq v4 Ultra Low Input RN from 8 paired samples in which tissue was available and passed the RNA quality control. Sequencing data was aligned with STAR and processed in R/Bioconductor. The counts matrix was obtained with featureCounts and differential expression paired analysis was performed with DESeq2. Gene set enrichment analysis (GSEA) was executed with the MSigDB collection.Results: A 49.62% decrease in Ki-67 staining was registered in all surgical specimens compared to baseline (p = 0.0003). Using the pre-specified response parameter (30% relative reduction) we identified 14/20 responders. Mifepristone was detected in all available plasma samples and the mean concentration was 308.33 ±57.91 ng/ml (716.71 ±134.62 nM). We conducted an RNA-seq analysis to explore changes at the transcript level. First, we conducted the study with all pairs of samples, without considering the response to MFP in Ki-67 studies. Unsupervised analysis showed the paired samples clustered together but neither the principal component analysis, nor the hierarchical clustering, showed any relevant cluster. The differential expression analysis identified 11 and 76 genes down- and up-regulated, respectively. We performed a GSEA based on KEGG databases and determined enriched pathways related to modulation of cell cycle and apoptosis. When the analysis was conducted with the REACTOME up-modulation of immune bioprocess and extracellular matrix re-modeling pathways such as degradation of extracellular matrix, activation of matrix metalloproteinases and collagen formation, were observed in the latter. Additionally, we observed down-modulation of pathways related to cell cycle such as DNA replication and synthesis, APC/C, and phase transition pathways. Interestingly, when we considered the tumors that responded to MFP according to Ki-67 data (n=4) and those that did not respond (n=4), we found that the non-responsive group shared some of the up and down modulated pathways as the responsive group.Conclusion: The results obtained in RNA-Seq data support the findings obtained by IHC indicating that MFP inhibits cell proliferation in luminal breast carcinomas with higher levels of PRA than PRB. The fact that MFP increased immune-related pathways is in line with previous preclinical data from our laboratory suggesting that MFP may prime this group of tumors for. further immune therapy. Interestingly, we found that some relevant pathways regarding inhibition of cell proliferation were also modulated in the non-responsive group suggesting that tumors in which a decrease in Ki-67 was not evident, may be still responding to MFP treatment. Ongoing analysis will determine changes in other markers that may help to further define MFP-responsive patients.

Citation Format: Andres Elia, Martin Abba, Hugo Gass, Caroline A Lamb, Victoria T Fabris, Paula Martinez Vazquez, Javier Burruchaga, Eunice Spengler, Ines Caillet Bois, Alejandra Castets, Silvia Lovisi, Marcos Liguori, Gabriela Pataccini, Maria Florencia Abascal, Virginia Novaro, Alfredo Molinolo, Silvia I Vanzulli, Paola Rojas, Claudia Lanari. Transcriptome modulation by mifepristone treatment in breast cancer patients with higher levels of progesterone receptor A than B [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-16-09.

Progesterone receptor isoform ratio dictates antiprogestin/progestin effects on breast cancer growth and metastases: A role for NDRG1

Progesterone receptors (PR) ligands are being tested in luminal breast cancer. There are mainly two PR isoforms, PRA and PRB, and their ratio (PRA/PRB) may be predictive of antiprogestin response. Our aim was to investigate: the impact of the PR isoform ratio on metastatic behavior, the PR isoform ratio in paired primary tumors and lymph node metastases (LNM) and, the effect of antiprogestin/progestins on metastatic growth. Using murine and human metastatic models, we demonstrated that tumors with PRB > PRA (PRB-H) have a higher proliferation index but less metastatic ability than those with PRA > PRB (PRA-H). Antiprogestins and progestins inhibited metastatic burden in PRA-H and PRB-H models, respectively. In breast cancer samples, LNM retained the same PRA/PRB ratio as their matched primary tumors. Moreover, PRA-H LNM expressed higher total PR levels than the primary tumors. The expression of NDRG1, a metastasis suppressor protein, was higher in PRB-H compared with PRA-H tumors and was inversely regulated by antiprogestins/progestins. The binding of the corepressor SMRT at the progesterone responsive elements of the NDRG1 regulatory sequences, together with PRA, impeded its expression in PRA-H cells. Antiprogestins modulate the interplay between SMRT and AIB1 recruitment in PRA-H or PRB-H contexts regulating NDRG1 expression and thus, metastasis. In conclusion, we provide a mechanistic interpretation to explain the differential role of PR isoforms in metastatic growth and highlight the therapeutic benefit of using antiprogestins in PRA-H tumors. The therapeutic effect of progestins in PRB-H tumors is suggested. This article is protected by copyright. All rights reserved.

The tale of TILs in breast cancer: A report from The International Immuno-Oncology Biomarker Working Group

The advent of immune-checkpoint inhibitors (ICI) in modern oncology has significantly improved survival in several cancer settings. A subgroup of women with breast cancer (BC) has immunogenic infiltration of lymphocytes with expression of programmed death-ligand 1 (PD-L1). These patients may potentially benefit from ICI targeting the programmed death 1 (PD-1)/PD-L1 signaling axis. The use of tumor-infiltrating lymphocytes (TILs) as predictive and prognostic biomarkers has been under intense examination. Emerging data suggest that TILs are associated with response to both cytotoxic treatments and immunotherapy, particularly for patients with triple-negative BC. In this review from The International Immuno-Oncology Biomarker Working Group, we discuss (a) the biological understanding of TILs, (b) their analytical and clinical validity and efforts toward the clinical utility in BC, and (c) the current status of PD-L1 and TIL testing across different continents, including experiences from low-to-middle-income countries, incorporating also the view of a patient advocate. This information will help set the stage for future approaches to optimize the understanding and clinical utilization of TIL analysis in patients with BC.

Abstract PS11-35: Mipra, a window of opportunity study evaluating mifepristone treatment for postmenopausal breast cancer patients with higher levels of progesterone receptor isoform a than b

Background: Different antiprogestins have been clinically evaluated in gynecological andbreast cancers. Mifepristone (MFP), as well as onapristone and telapristone acetate, showedpartial responses in breast cancer clinical trials. Preclinical data indicates that antiprogestinsinhibit cell proliferation of luminal breast carcinomas expressing higher levels of progesteronereceptor isoform A (PRA) than those of isoform B (PRB) evaluated by western blots (WB). Thus,we designed a pre-surgical window trial to determine the therapeutic effects of oral MFP oncell proliferation and on differential gene expression in 20 breast cancer patients selected bytheir high PRA/PRB isoform ratio.Methods. MIPRA is an open-label, one-arm, prospective interventional study (NCT02651844).We interviewed 140 naive breast cancer patients and 133 accepted to participate. Four coreultrasound-guided biopsies were performed, two were formalin-fixed for diagnosis, ER, PR,HER2, and Ki67 evaluation and two were snap-frozen for WB and molecular studies. Patientsthat met the inclusion criteria, with ER+, PRA/PRB&gt;1.5 and total PR ≥50% determined by WBand immunohistochemistry (IHC), respectively, were included for MFP treatment. Plasma wasobtained before and after treatment for future studies. Patients were treated with oral MFP(200 mg/day) for 14 days before surgery which was performed on day 15. Clinical examinationwas performed at days 7 and 14 to register possible adverse effects and to measure tumorsize. During surgery, samples were formalin-fixed for IHC studies, and others were snap-frozenfor further molecular studies. One patient had a bilateral breast cancer, and both tumorsmatched with the inclusion criteria and were included. The primary endpoint was Ki67labeling, comparing diagnostic core needle biopsy to post-therapy surgical specimens.Considering previous studies performed with tamoxifen, we pre-specified that 30% of relativereduction in Ki67 would be considered as a positive response. Differences in Ki67 expressionwere quantitated by an expert pathologist counting at least ten 40x fields per slide. Theseresults are currently being validated by a second pathologist. One patient, with a core biopsywith less than 500 total cells, was excluded. Ongoing experiments include secondary and otherendpoints: comparison of apoptotic, proliferative and hormone receptor markers by IHC,measurement of MFP plasma levels and, RNAseq analysis in samples pre- and post-treatment. Ki67 changes from baseline were tested with paired Wilcoxon matched-pairssigned-rank test.Results: The median (range) Ki67 value of biopsies was 11.87% (2.70- 34.56) and for surgicalspecimens was 6.45% (0.48-23.77). A 45.67% of decrease in the median % Ki67 (41.63%comparing the arithmetic mean values and 50.83% comparing the geometric mean values) wasregistered in all surgical specimens compared to baseline (p= 0.003). Using the pre-specifiedresponse parameter (30% relative reduction in Ki67), we identified 15/20 (75%) responders.Considering only responsive tumors, a 49.87% decrease in the median % Ki67 (50.83%,arithmetic mean; 62.34% geometric mean) was observed (p&lt;0.0001) between baseline andsurgical specimens. In those cases with the highest response, the decrease in Ki-67 wasaccompanied by a decrease in tumor volume (ultrasound measurements).Conclusion: Our results show that MFP treatment may be effective in patients showing a highPRA/PRB ratio. The magnitude of the inhibition was similar or higher to that reported fortamoxifen in ER+ breast cancer patients in short-term treatment studies. Ongoing analysis willdetermine if there are changes in other markers that may help to further define MFP-responsive patients.

Citation Format: Andres Elia, Silvia I Vanzulli, Hugo Gass, Caroline A Lamb, Victoria T Fabris, Paula Martinez Vazquez, Javier Burruchaga, Eunice Spengler, Ines Caillet Bois, Alejandra Castets, Silvia Lovisi, Marcos Liguori, Gabriela Pataccini, M Florencia Abascal, Virginia Novaro, Gabriela Acosta Haab, Alfredo Molinolo, Paola Rojas, Claudia Lanari. Mipra, a window of opportunity study evaluating mifepristone treatment for postmenopausal breast cancer patients with higher levels of progesterone receptor isoform a than b [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS11-35.