Vachon, Celine M.

Abstract Introduction: Although Hispanic White (HW) females have a lower incidence of breast cancer than non-Hispanic White (NHW) females, breast cancer risk is unclear for HW females after benign breast disease (BBD). Methods: We compared BBD characteristics and subsequent breast cancer risk among HW and NHW females in New Mexico using a population-based collection of benign breast biopsies (1996–2007). BBD was categorized as nonproliferative disease (NPD), proliferative disease without atypia (PDWA), or atypical hyperplasia (AH). Breast cancer risk was assessed as absolute risk (AR) using cumulative incidence and RR by comparing the number of breast cancer events in BBDs to non-BBD. Results: This study included 3,684 HW and 6,587 NHW females with BBD. HW females had similar proportions of NPD (58.6% vs. 54.3%), PDWA (21.4% vs. 23.5%), and AH (3.6% vs. 3.3%) as NHW females. Breast cancer risk among all females with BBD was higher than population-based expected rates (RR, 1.87) and was similar for HW and NHW subgroups (RR = 1.99 vs. 1.84). As expected, breast cancer risk increased with increasing BBD severity, both overall [RR, 1.81 (NPD), 1.85 (PDWA), and 3.10 (AH)] and in the HW and NHW subgroups. Adjusted AR of breast cancer at 5 years also increased with the severity of BBD (HW vs. NHW; NPD: 1.4% vs. 2.1%; PDWA: 1.5% vs. 2.7%; AH: 6% vs. 4.8%). Conclusions: We found similar breast cancer RRs and ARs in HW and NHW. Risk counseling should ensure that HW females receive breast cancer clinical management warranted by their similar absolute risks. Impact: The present population-based provides evidence for the clinical management of HW females with BBD for the prevention of breast cancer.

Abstract Objectives: Mammographic microcalcifications (calcs) are a sentinel marker of in-situ and invasive breast cancer (BC) but most calcs reflect benign breast disease (BBD). BBD comprises a diverse set of lesions, variably associated with increased BC risk. While calc frequency data for the modern era are limited, historically, calcs were reported in 11% of BBD biopsies. Some studies suggest that calcs in BBD impact BC risks; however, the frequency and BC risks associated with calcs during the percutaneous biopsy era have not been clearly established. Accordingly, we assessed the association of calcs with specific BBD lesions and BC risk in a large contemporaneous BBD cohort including detailed pathology review. Methods: A cohort of 4,819 patients with percutaneously diagnosed BBD from 2002-2013 at Mayo Clinic, were identified. The cohort was followed from 6 months after biopsy until censoring, BC diagnosis, or December 2021. Mean follow-up was 11.3 (SD=5.1) years for BBD patients who remained cancer-free in follow-up compared with 7.4 (SD=4.3) years for cases. Histology of all biopsies were reviewed microscopically to record pathologic findings. A natural language processing algorithm (NLPA) was developed and utilized to identify the presence of calcs based on pathology reports. NLPA results were compared to 300 matched biopsy reports, taken as ground truth. We performed age-adjusted Cox proportional hazards regression to assess hazard ratios (HRs) with 95% confidence intervals (CIs) for specific BBD lesions, stratified by the presence (calc+) or absence of calcs (calcs-), with estimation of an interaction term to test for differences in risks by calc strata. Standardized incidence ratios (SIRs) estimated risks for calc+ and calc- BBD lesions versus matched strata for Iowa SEER population-based BC incidence rates. Results: The NLPA achieved sensitivity=0.993 and specificity=0.986. Overall, 42.8% of BBD biopsies were calc+, including 49.1% of biopsies preceding BC and 42.4% of biopsies not preceding BC (Chi-square p=0.02). Overall, risks of BC among women with BBD calc+ biopsies did not differ significantly from those of women with calc- BBD: HR=1.13 (95% CI: 0.90,1.41), p=0.290. SIRs were also similar for the two groups; women with BBD calc+ biopsies had an SIR =2.00 (95% CI: 1.72, 2.33) and BBD calc- biopsies yielded an SIR= 1.91 (95% CI: 1.64,2.22) (Table 1). HRs were similar for specific calc+ and calc- BBD lesions, with progressively higher risks for non-proliferative disease (NP), proliferative disease without atypia (PDWA) and atypical hyperplasia (AH) (pinteraction=0.55). Interaction terms were not significant for any specific lesion, apart from a marginally significant result for dilated ducts, wherein risks were marginally higher for calc- lesions (pInteraction =0.048), perhaps representing a chance finding. SIRs for calc+ versus calc- BBD lesions were also similar. Overall, 77.3% of AH was calc+; for AH calc+, SIR=3.76 (95%CI: 2.74-5.17) and for AH calc-, SIR=4.41 (95%CI: 2.56-7.59). Conclusion: In this recent, larger percutaneous BBD cohort, calcs were present in 42.8% of all specimens, representing a marked increase compared with historical BBD data, particularly those dominated by surgical biopsy for diagnosis and preceding implementation of full-field digital mammography. In this study, calcs in percutaneously diagnosed BBD were not associated with increased BC risk. Table 1: Comparison of standard incidence ratio of subsequent breast cancer with and without microcalcifications in benign breast disease by histologic impression (NP = non-proliferative disease, PDWA = proliferative disease without atypia, and AH = atypical hyperplasia). (1) compared to Iowa SEER population Citation Format: Sarah Schrup, Robert Vierkant, Stacey Winham, Celine Vachon, Derek Radisky, Jodi Carter, Laura Pacheco-Spann, Matthew Jensen, Amy Degnim, Mark Sherman. Benign breast disease and microcalcifications in percutaneous biopsies and breast cancer risk [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS07-02.

Abstract Artificial intelligence (AI) models based on deep learning of mammogram images have been developed for lesion detection and diagnosis as well as breast cancer (BC) risk. We and others have shown that these AI models, coupled with breast density, predict long-term breast cancer risk. Common germline genetic variation, in particular a polygenic risk score (PRS) that captures the cumulative impact of hundreds of common risk variants, has been shown associated with 3-fold increased BC risk. The BC-PRS may complement imaging risk factors to improve identification of women at high BC risk and better target prevention strategies. We evaluated the contribution of a BC-PRS to two imaging-based AI models (Transpara AI cancer detection system and Mirai 5-year risk) and breast density measures to long-term BC risk. We hypothesized that the BC-PRS will improve long-term risk prediction above AI and density measures. We examined this hypothesis within a cohort of 10,271 women enrolled to the Mayo Clinic Biobank between 2009 and 2015. Eligible women had no prior cancer, were ages 35 to 85, had a full-field digital screening mammogram within two years of enrollment and genotyping by Regeneron. Incident invasive and DCIS BC was identified through the Mayo tumor registry and follow-up questionnaires, and person years were calculated from date of mammogram through date of BC, last mammogram at Mayo or last questionnaire. We estimated Transpara AI malignancy score (1-10), 5-year Mirai risk and Volpara volumetric density measures (volumetric percent density, dense volume) on screening mammograms at enrollment and obtained clinical BI-RADS density. We calculated the BC-PRS using 268 SNPs (of the 313-SNP score) and the weighted sum of the SNPs using odds ratios from the largest BC GWAS of European ancestry to date. We performed cox proportional hazards regression adjusting for age and BMI to estimate hazard ratios (HRs), 95% confidence intervals (CI), and C-statistics (AUC) to describe the contribution of BC-PRS (per standard deviation (SD)) to the association of AI scores and breast density with BC risk. Likelihood ratio tests (LRT) and bootstrapping were used to compare model performance with vs. without inclusion of BC-PRS, at 10-years follow-up. Comparisons to the Tyrer-Cuzick model are ongoing. Over a median of 9.1 years (Interquartile range, 6.8 to 10.6), 446 incident BC were identified of which 285 invasive and 103 DCIS were confirmed by pathology report (60 were self-reported); 399 (256 invasive) occurred within 10 years and were used in primary analyses. Transpara score [HR per 1 unit=1.18 (1.14, 1.23), AUC=0.655 (0.628, 0.682)] and Mirai risk [HR per SD log risk=1.54 (1.43, 1.65), AUC=0.681 (0.655, 0.706)] were both associated with BC. All three breast density measures were also significantly associated with BC, including in models with AI scores (Table). Addition of the BC-PRS to models with AI scores and breast density improved both model fit (All PLRT < 0.001; Table) and discrimination, with increases in AUC ranging from 0.033 to 0.034 for models with Transpara and density and 0.025 to 0.026 for models with Mirai and density (all P-values < 0.001; Table). Analyses restricted to invasive BC showed identical results. But, the BC-PRS contribution at 5-year follow-up was attenuated. In this cohort study, we found BC-PRS contributed to long-term risk prediction of BC above imaging AI models and breast density. Imaging and genetic risk factors are complementary and may outperform existing risk models and provide more accurate risk assessment to aid in precision prevention strategies. Citation Format: Celine Vachon, Christopher Scott, Imon Banerjee, Ramon Correa Moderno, Dan Hursh, Matthew Jensen, Yvonne Wang, Kathleen Brandt, Karla Kerlikowske, Sandhya Pruthi, Fergus Couch, Stacey Winham. Contribution of a breast cancer polygenic risk score to mammography artificial intelligence models and breast density for long term breast cancer risk prediction [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS10-06.

Abstract Artificial intelligence (AI) models applied to mammography have been shown to improve breast cancer (BC) detection and risk estimation. The Transpara AI detection system has been associated with short and longer-term risk of invasive BC. Whether Transpara can identify changes in the breast associated with tamoxifen (TAM) and aromatase inhibitor (AIs) treatment is unknown. We compare changes in the Transpara malignancy score in the unaffected breast of BC cases using TAM or AIs to those of untreated women without cancer. Cases and controls were sampled from the Mayo Clinic Rochester Breast Screening Practice. Eligible cases were women with breast cancer treated with TAM and/or AIs for at least 8 months who had full field digital (FFDM) mammograms within two years prior to start of treatment (pretreatment mammogram). Controls did not have BC, were not using TAM, AIs, or postmenopausal hormones, and had at least two FFDM screening mammograms. Transpara scores (1-10) were calculated for the contralateral breast in cases and a randomly selected side for controls. Two controls were matched to each case on menopausal status at both mammograms, time between mammograms (< 6 months) and baseline Transpara score (±2 units). Conditional logistic regression was used to assess the association of treatment (case (TAM/AIs) vs. control) with change in Transpara score between the pretreatment mammogram and the mammogram taken closest to 13 months later. Change was classified as having a decrease in Transpara score between the two mammograms vs. no change or an increase. Models were adjusted for age and Transpara score at pretreatment mammogram, and time between the two mammograms. We performed analyses on all women combined and stratified by time on treatment, menopausal status, and treatment type (TAM vs. AIs). A total of 134 cases were identified, with 53 on TAM (21 premenopausal and 32 postmenopausal) and 81 on AIs (postmenopausal); 268 controls were matched to the cases. Characteristics of the study population are summarized (Table). Most case mammograms were obtained within six months prior to treatment start [median 2.63 months (interquartile range (IQR), 1.62, 5.72)] and median time on TAM/AIs was 10.9 months (IQR, 8.03, 16.6) at time of second mammogram. The median absolute change in Transpara score between the two mammograms was similar in cases [0 (IQR, -2, 1)] vs. controls [0 (IQR, -1.25, 1)]; 40.3% of cases and 39.2% of controls had any decrease. Conditional logistic models found no evidence for an association between TAM/AIs and decrease in Transpara score [odds ratio (OR) = 1.07; 95% confidence interval (CI), 0.65, 1.78]. When stratified by median time on treatment (10.9 months), there was suggestion of a stronger association for those on treatment for a longer duration (OR = 1.21; 95% CI, 0.61, 2.40 for >10.9 months vs. OR = 0.96; 95% CI, 0.43, 2.13 for < 10.9 months) but these results were not statistically significant. Similarly, odds ratios were stronger in postmenopausal (OR = 1.18; 95% CI, 0.67, 2.07) compared to premenopausal (OR = 0.91; 95% CI, 0.24, 3.45) women, and for AIs (OR = 1.21, 95% CI, 0.64, 2.29) vs. TAM (OR = 0.93; 95% CI, 0.39, 2.22) but none of these results reached statistical significance. In summary, we found no association between treatment with TAM/AIs and change in Transpara score. However, our study had limited power. Also, longer time on treatment as well as investigation of AI-based scores trained directly to assess BC risk may be necessary to identify relevant changes. Citation Format: Yvonne Wang, Christopher Scott, Matthew Jensen, Dan Hursh, Kathleen Brandt, Aaron Norman, Fang Fang Wu, Stacey Winham, Karla Kerlikowske, Celine Vachon. Changes in an artificial intelligence model score for breast cancer detection (Transpara) with tamoxifen and aromatase inhibitor treatment [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-09-04.

Abstract Over 1 million women in the U.S. undergo radiologically guided percutaneous biopsies annually. Of these, 75% reveal benign breast disease (BBD), typically surrounded by normal breast lobules, which are proposed to reflect the biology of the breast parenchyma diffusely. With aging, normal lobules undergo involution, and delays in this process are linked to increased breast cancer (BC) risk. Because BBD patients are at increased risk of developing BC, and pathologic classification only stratifies risks among groups of patients, novel methods for individual BC risk prediction are needed to guide precision management. Prior literature has shown that most proliferating epithelial cells in normal lobules do not express estrogen receptor (i.e., ER-/Ki67+), whereas co-expression is frequent in BC precursors and in BCs (i.e., ER+/Ki67+). Thus we developed and applied a novel quantitative dual ER/Ki67 stain to BBD biopsies from the well-characterized contemporary Mayo Clinic BBD cohort (2002-2013) to assess differences by levels of lobular involution and tissue type (BBD vs. normal), as well as associations with BC risk. We identified 100 BBD biopsies preceding BC (cases) and 100 biopsies from cancer-free women (controls), frequency-matched on age and length of follow-up. A multiplex immunofluorescence assay was developed to detect ER/Ki67 coexpression in cytokeratin positive epithelial cells in normal lobules or BBD lesions in FFPE tissue sections. An inverse normal transformation was applied to cell counts and proportions and associations were assessed for levels of lobular involution, tissue type (normal lobule vs. BBD), and case status using t-tests and linear regression models. The final data set included 1152 normal lobules or BBD lesions in biopsies of 177 subjects (88 cases and 89 controls). In univariate analyses, normal lobules showing delayed age related involution included higher counts of ER-/Ki67+, ER+/Ki67- and ER+/Ki67+ cells, and the lowest proportion of ER+/Ki67- cells (p<0.03; all). In separate analyses comparing presence vs. absence, detection of any ER+/Ki67+ cells was suggestively more common in non-involuted vs. involuted lobules. Compared with normal lobules, BBD showed higher counts and proportions of ER+/Ki67- and ER+/Ki67+ cells and lower values for ER-/Ki67+ (all p<0.001). In these preliminary results, marker expression in normal lobules and in BBD did not differ by case-control status. Preliminarily, we find that ER+/Ki67+ cells are increased in normal lobules with delayed age-related involution and in BBD lesions, consistent with their associations with increased BC risk. These findings are consistent with the risk reducing effects of endocrine chemoprevention and may serve as useful biomarkers in prevention therapy. In this analysis, limited to only a few lobules and BBD lesions per biopsy, ER+/Ki67+ cell counts and proportions did not vary significantly by case-control status. Citation Format: Melody L. Stallings-Mann, Robert A. Vierkant, Stacey J. Winham, Bryan McCauley, Matt R. Jensen, Sophie Noel, Laura Pacheco-Spann, Celine M. Vachon, Amy C. Degnim, Derek C. Radisky, Mark E. Sherman. Measurement of ER and Ki67 coexpression in cytokeratin positive epithelial cells in benign breast disease (BBD) percutaneous biopsies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB328.

Abstract Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant condition characterized by plasma cell production of monoclonal (M) protein and is a requisite precursor to multiple myeloma (MM). African American (AA) individuals have a two-fold higher incidence of MGUS and MM compared to White individuals. However, data are limited on individuals from Africa, especially using sensitive MGUS detection methods. We examined the prevalence of MGUS in a sample of the general population in Nigeria. Individuals aged 40 and over (n=343) were recruited through health promotion events in Ado-Odo Ota Local Government Area of Ogun State, Nigeria, and provided informed consent, a blood sample, and a short questionnaire. Serum was screened at Mayo Clinic for heavy chain (HC)-MGUS using the matrix-assisted laser desorption/ionization-time of flight (Mass-Fix) assay, which has high sensitivity for detection of M-proteins; serum free light chains (FLC) were also measured. FLC was abnormal if the kappa (>0.26 mg/dL) or lambda (>0.33 mg/dL) light chain (LC) was elevated and FLC ratio (kappa/lambda) was outside the reference range (0.26-3.10). LC-MGUS was defined as an abnormal FLC in the absence of a HC. Age- and sex-adjusted prevalence rates were directly standardized to 2010 United States (US) population for comparison to published studies. Logistic regression was used to examine the association of age, sex, and BMI with HC-MGUS. The mean age of participants was 55 years (SD=10.9), and 74.6% were female. Of these, 216 (63%) had both parents from the Yoruba tribe, 89 (26%) from the Igbo tribe and 38 (11%) from other tribes. Overall, 33 participants (9.6%) had HC-MGUS, with 8 (2.3%) having an M-protein above 0.2 g/dL; 6 (1.7%) had LC-MGUS. HC-MGUS was predominantly IgG isotype (48.5%), followed by IgA (27.3%), biclonal (15.2%) and IgM (9.0%). Prevalence of HC-MGUS was 8.3% for ages 40-49, 7.7% ages 50-69 and 22% ages 70 and above. Standardized to the US population, age and sex adjusted MGUS prevalence ages 50 and older was 17.3% (95% CI: 9.8%-24.9%) and HC-MGUS was 14.7% (95% CI: 7.7%-21.8%), similar to previously published rates of HC-MGUS using Mass-Fix screening of AA individuals (16.5%, 95% CI: 12.2%-20.8%) (PMID: 35316833). In models that included age, sex and BMI, older age was positively associated with HC-MGUS (OR=3.1, 95% CI: 1.1-8.7 for ages 70+ compared to <50), while female sex (OR=0.53, 95% CI: 0.24-1.2) and overweight/obesity (OR=0.34, 95% CI: 0.16-0.75 for BMI > 25 vs. <25) were inversely associated with HC-MGUS. We observed similar prevalence of HC-MGUS at ages 50 and above among Western Nigerian and AA populations when screened using mass-spectrometry. Older age was positively associated with HC-MGUS while overweight and obesity were inversely associated. Studies of MGUS in indigenous African populations may provide insight to unique cancer risk factors compared to other populations. Citation Format: Celine M. Vachon, Cristine Allmer, Danelle Moonen, Aaron Norman, Joselle Cook, Susan Slager, Oluwakemi A. Rotimi, Opeyemi C. De Campos, Titilope M. Dokumu, David Murray, Shaji Kumar, Elizabeth Brown, Linda B. Baughn, Solomon Rotimi. Prevalence of monoclonal gammopathy of undetermined significance (MGUS) in a Western Nigerian population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3455.

Abstract Chronic Lymphocytic Leukemia (CLL) exhibits a substantial familial risk that extends beyond CLL to other B-cell lymphomas (including follicular lymphoma and diffuse large B-cell lymphoma). Monoclonal B-cell Lymphocytosis (MBL), a precursor to CLL, is also associated with a significant risk for hematologic malignancies overall and for lymphoid malignancies, specifically. Moreover, previous research has shown an association between the CLL polygenic risk score (CLL-PRS) and common lymphoma subtypes. This study aims to further evaluate CLL-PRS associations with hematological cancer overall and by lineage while also considering MBL status a strong risk factor for lymphoid malignancies. Utilizing the Mayo Clinic Biobank, we selected individuals aged 40 years or older, residing in proximal counties, who had no prior hematologic malignancies, and with available biospecimens. MBL screening was done using 8-color flow cytometry, and MBL with CLL (CD5+/CD20dim) or atypical CLL (CD5+/CD20+) immunophenotype were included. CLL-PRS was calculated from 41 known susceptibility variants, with weights being the log of the odds ratios from the largest CLL genome-wide association study. Incident hematologic malignancies were ascertained through ICD codes and confirmed via medical record review. Hazard ratios (HR) and 95% confidence intervals (CIs) for associations with hematologic malignancies were estimated through Cox regression. Of 7,332 participants, 1,150 (16%) screened positive for MBL; median age was 67 years (range 40-101), and 37% male. Median follow-up was 2.9 years (range 0-13), and 56 hematologic cancers were identified. After adjusting for age and sex, the CLL-PRS was associated with increased risk of developing hematologic (HR=1.49, 95%CI=1.12-1.98, P=0.006) which was all attributable to lymphoid cancers (HR=1.79, 95%CI=1.26-2.56, P=0.001). When adjusting for baseline MBL status in the models, the CLL-PRS associations remained significant but were attenuated for hematological (HR=1.33, 95%CI=0.99-1.79, P=0.058) and lymphoid (HR=1.56, 95%CI=1.07-2.26, P=0.020) malignancies, while MBL status was also significantly associated with risk of hematologic (HR=2.76, 95%CI=1.55-4.91, P=0.001) and lymphoid (HR=3.61, 95%CI=1.78-3.32, P<0.001) malignancies. In this prospective cohort study of individuals screened for MBL, CLL-PRS was associated with an elevated risk of hematologic malignancies overall and within the lymphoid lineage, underscoring a shared genetic etiology across many B-cell lymphomas. However, the associations between CLL-PRS and hematologic malignancies were attenuated when accounting for MBL status or when analyzing among MBL-positive individuals, highlighting the role of MBL status in these associations. Further research with expanded cohorts is needed to unravel these complex genetic and clinical interactions. Citation Format: Raphael Mwangi, Dennis P. Robinson, Sara J. Achenbach, Geffen Kleinstern, Aaron D. Norman, Kari G. Rabe, Janet E. Olson, Neil E. Kay, Rosalie Griffin, Nicholas J. Boddicker, Esteban Braggio, Sameer A. Parikh, Curtis A. Hanson, Celine M. Vachon, James R. Cerhan, Tait D. Shanafelt, Susan L. Slager. Genetic associations with hematologic malignancies: An evaluation of CLL polygenic risk score and MBL status in the Mayo Clinic Biobank Cohort [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6152.

Abstract High-count monoclonal B-cell lymphocytosis (HCMBL) is a precursor condition to chronic lymphocytic leukemia (CLL). We have shown that among individuals with HCMBL, the CLL-International Prognostic Index (CLL-IPI) is prognostic for time-to-first therapy (TTFT). Little is known about the prognostic impact of somatically mutated genes among individuals with HCMBL. We sequenced DNA from 371 individuals with HCMBL using a targeted sequencing panel of 59 recurrently mutated genes in CLL to identify high-impact mutations. We compared the sequencing results with that of our treatment-naïve CLL cohort (N = 855) and used Cox regression to estimate hazard ratios and 95% confidence intervals (CIs) for associations with TTFT. The frequencies of any mutated genes were lower in HCMBL (52%) than CLL (70%). At 10 years, 37% of individuals with HCMBL with any mutated gene had progressed requiring treatment compared with 10% among individuals with HCMBL with no mutations; this led to 5.4-fold shorter TTFT (95% CI, 2.6-11.0) among HCMBL with any mutated gene vs none, independent of CLL-IPI. When considering individuals with low risk of progression according to CLL-IPI, those with HCMBL with any mutations had 4.3-fold shorter TTFT (95% CI, 1.6-11.8) vs those with none. Finally, when considering both CLL-IPI and any mutated gene status, we observed individuals with HCMBL who were high risk for both prognostic factors had worse prognosis than patients with low-risk CLL (ie, 5-year progression rate of 32% vs 21%, respectively). Among HCMBL, the frequency of somatically mutated genes at diagnosis is lower than that of CLL. Accounting for both the number of mutated genes and CLL-IPI can identify individuals with HCMBL with more aggressive clinical course.

Abstract Monoclonal B-cell lymphocytosis (MBL) progresses to chronic lymphocytic leukemia (CLL) requiring therapy at 1% to 5% per year. Improved prediction of progression would greatly benefit individuals with MBL. Patients with CLL separate into 3 distinct epigenetic subtypes (epitypes) with high prognostic significance, and recently the intermediate epitype has been shown to be enriched for high-risk immunoglobulin lambda variable (IGLV) 3-21 rearrangements, impacting outcomes for these patients. Here, we employed this combined strategy to generate the epigenetic and light chain immunoglobulin (ELCLV3-21) signature to classify 219 individuals with MBL. The ELCLV3-21 high-risk signature distinguished MBL individuals with a high probability of progression (39.9% and 71.1% at 5 and 10 years, respectively). ELCLV3-21 improved the accuracy of predicting time to therapy for individuals with MBL compared with other established prognostic indicators, including the CLL international prognostic index (c-statistic, 0.767 vs 0.668, respectively). Comparing ELCLV3-21 risk groups in MBL vs a cohort of 226 patients with CLL revealed ELCLV3-21 high-risk individuals with MBL had significantly shorter time to therapy (P = .003) and reduced overall survival (P = .03) compared with ELCLV3-21 low-risk individuals with CLL. These results highlight the power of the ELCLV3-21 approach to identify individuals with a higher likelihood of adverse clinical outcome and may provide a more accurate approach to classify individuals with small B-cell clones.