Immune microenvironment dynamics in breast cancer during pregnancy: impact of gestational age on tumor-infiltrating lymphocytes and prognosis

Background

Breast cancer during pregnancy (PrBC) is a rare condition known for its aggressive clinical behavior. The presence of tumor-infiltrating lymphocytes (TILs) has been shown to have a significant impact on the prognosis of these patients. Despite some biological characteristics of the tumor that may differ depending on the gestational age, little is known about the dynamics of the immune landscape within the tumor microenvironment (TME) in PrBC. Therefore, in this study, our objective was to gain comprehensive insights into the relationship between gestational age at breast cancer diagnosis and the composition of the TME.

Methods

n = 108 PrBC were selected from our institutional registry and categorized based on the gestational age by trimester. For all cases, TILs were profiled according to the International TILs Working Group recommendations, and subtyped by CD4, CD8, and forkhead box P3 (FOXP3) immunohistochemistry. PD-L1 was tested according to the combined positive score (CPS) using the IHC 22C3 pharmDx assay, with a cutoff value of ≥10 for positivity. The statistical approach encompassed Fisher's and Chi-squared tests, with appropriate adjustments for multiple comparisons, logistic regression models, and survival analyses based on the Kaplan-Meier method.

Results

The proportion of patients with poorly differentiated (G3) neoplasms increased as the gestational age advanced (first trimester, n = 25, 56.8%; second trimester, n = 27, 69.2%; third trimester, n = 21, 87.5%; p = 0.03). The histologic subtypes as well as the hormone receptor (HR) and HER2 status did not show significant changes across different pregnancy trimesters. In the HR+/HER2- subtype, there was a higher proportion of tumors with high/moderate TILs in the early phases of pregnancy, similar to FOXP3 expression (TILs: first trimester, n = 10, 35.7%; second trimester, n = 2, 10.5%; third trimester, n = 0; p = 0.02; FOXP3: first trimester, n = 10, 40%; second trimester, n = 3, 15.8%; third trimester, n = 0; p = 0.03). The median follow-up for our cohort was 81 months. Patients who relapsed after a breast cancer diagnosis during the first trimester were more frequently PD-L1-negative, unlike those with no disease recurrence (n = 9, 100% vs. n = 9, 56.3%; p = 0.03; hormone therapy and n = 9, 100% vs. n = 7, 53.9%; p = 0.02; chemotherapy). No statistically significant differences were seen among the three trimesters in terms of survival outcome.

Conclusion

The TME dynamics of HR+/HER2- PrBC vary based on gestational age, suggesting that immune tolerance expression during later gestational age could explain the increased aggressiveness of tumors diagnosed at that stage.

Abstract P2-21-04: The tumor immune microenvironment composition and prognostic value in breast cancer during pregnancy is dynamic during the gestation period

Introduction: Breast cancer (BC) during pregnancy (PrBC) is an uncommon malignancy characterized by a more aggressive clinical course compared to pregnancy-unrelated BC. Specific patterns of tumor-infiltrating lymphocytes (TILs) subpopulations have been observed in these patients, with significant prognostic roles. Previous studies demonstrated the varying histopathologic and prognostic profiles of PrBC by gestational age. However, the underlying immune landscape dynamics has never been investigated. Here, we sought to provide comprehensive insights into the association between gestational age at breast cancer diagnosis and tumor immune microenvironment (TIME) composition. Materials and Methods: A total of 110 PrBC were selected from our Institutional registry and categorized based on the trimester in which they were diagnosed. All cases were subjected to TILs profiling according to the International TILs Working Group recommendations. Immunohistochemistry for CD4, CD8, forkhead box P3 (FOXP3), and PD-L1 (clone 22C3) on a Dako Omnis platform was performed. Fisher’s and Chi-squared tests, multinomial logistic regression models, ROC curve, and survival analyses were performed. Results: The proportion of patients with high histologic grades incremented with the increase in gestational age (1st, n=24, 53%; 2nd, n=27, 69.2%; 3rd trimester, n=20, 87.0%; p=0.02). Neither breast cancer subtypes nor the hormone receptor (HR) and HER2 status changed significantly according to the pregnancy trimester. In HR+/HER2- subtype, the proportion of TILs+ tumors were higher in the early phases of pregnancy (1st, n=29, 100%; 2nd, n=17, 89.5%; 3rd trimester, n=9, 81.8%; p=0.04) imprinted by FOXP3 positivity where more FOXP3+ TILs were seen in the first months and decreased progressively (1st, n=10, 55.6%; 2nd, n=2, 11.8%; 3rd trimester, n=0, 0%; p< 0.01)). While in the triple negative breast cancer (TNBC) population, the proportion of PD-L1+ tumors (i.e. CPS>1) was significantly higher in the later stages of pregnancy (1st, n=2, 16.7%; 2nd, n=2, 18.2%; 3rd trimester, n=5, 71.4%; p=0.03). Patients who relapsed after a BC diagnosis during the 1st and 2nd trimesters lacked more frequently FOXP3+ and CD8+ cells, unlike those with no disease recurrence (n=21, 77.8% vs. n=17, 48.6%; p=0.02 and n=18, 66.7% vs. n=10, 28.6%; p< 0.01, respectively). Conclusions: TIME dynamics of PrBC are different according to the gestational age in both HR+ and TNBC PrBC. Our results suggest that immune tolerance events are likely to involve PrBC at later gestational age. Specific escape mechanisms (i.e., TILs and FOXP3 decrease in HR+ and PD-L1 expression in TNBC) might explain the aggressiveness of PrBC diagnosed during the later gestational age.

Citation Format: Elham Sajjadi, Konstantinos Venetis, Mariia Ivanova, Marianna Noale, Concetta Blundo, Giovanna Scarfone, Eugenia Di Loreto, Stefano Ferrero, Stefania Maggi, Paolo Veronesi, Viviana Enrica Galimbreti, Giuseppe Viale, Fedro Alessandro A. Peccatori, Elena Guerini-Rocco, Nicola Fusco. The tumor immune microenvironment composition and prognostic value in breast cancer during pregnancy is dynamic during the gestation period [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-21-04.

Abstract P4-07-02: Tumor microenvironment characteristics and prognosis in breast cancer during pregnancy: The role of differentially expressed immune-related genes

Introduction: Breast cancer during pregnancy (PrBC) accounts for ~4% of breast cancer cases in young women and its intrinsic biology is still largely undetermined. Tumor microenvironment (TME) of PrBC has been recently characterized with low levels of stromal tumor-infiltrating lymphocytes (TILs) and high relative expression of programmed death-ligand 1 (PD-L1), suggesting an increased immune evasion. The underlying immune landscape, however, has not been unveiled. Given the significant alterations of the immune system during gestation, we hypothesized that the TME of PrBC might have distinct biological traits. Here, we sought to evaluate the outcome of PrBC according to the TME characteristics and to assess whether pathogenic mechanisms of immune evasion are involved. Methods: Representative formalin-fixed paraffin-embedded tissue blocks of 83 consecutive PrBC and 89 age-matched early-onset pregnancy-unrelated breast cancers (controls) were subjected to immunohistochemistry (IHC) using antibodies against CD4, CD8, forkhead box P3 (FOXP3), and PD-L1 (clone 22C3) on a Dako Omnis platform. For all cases, TILs were evaluated according to the International TILs Working Group recommendations. Next-generation sequencing gene expression of 395 genes involved in tumor-immune interactions (Oncomine™ Immune Response Research Assay) was performed on RNA extracted from PrBC (n=20) and controls (n=16). Samples with mapped reads >1,000,000 and valid reads >800,000 were considered adequate. Fisher’s and Chi-squared tests, multinomial logistic regression models, ROC curve, and survival analyses were performed. Results: The fraction of tumors with CD8+TILs was significantly higher in PrBC than in the controls (n=71(85.0%) vs. n=61(68.5%); p=0.02), being mirrored by less cases with CD4+TILs (n=27 (32.5%) vs. n=43 (48.3%); p=0.03). Even higher differences were observed in hormone receptor (HR)+/HER2-negative tumors (CD8: n=39 (88.6%) vs. n=39 (66.1%); p=0.01). After a median follow-up of 78 (range, 1-247), 66/83 women (79.5%) with PrBC were alive and 53/83 (63.8%) relapse-free. Overall, PrBC with CD8+TILs had a better outcome compared to CD8-negative PrBC (OS 81 vs 69 months p=0.05) and CD8 expression was associated with better outcomes in HR+/HER2-negative tumors (OS p=0.02; DFS p=0.04). The overall comparison of immune-related genes in the 34 cases (PrBC, n=18; controls, n=16) that reached the quality parameters revealed significant differences in the expression of 63 immune-related genes. Of these, 4 genes (IFNA17, IFNB1, FUT4, and PECAM1) were upregulated, while 59 genes were downregulated in PrBC compared to the controls. Interestingly, IFNA17, IFNB1, and FUT4 remained upregulated in HR+ PrBC, where a slightly reduced number of differentially expressed genes was observed (n=60). In HR-/HER2- PrBC, only 25 genes were differentially expressed, of which 9, including IFNA17 and PECAM1, were significantly upregulated. Discussion: These data have the potential of improving our knowledge of the immunobiology that characterizes PrBC, suggesting that in these tumors the higher frequency of CD8+TILs might be related to an enhanced anti-tumor immune response, as CD8 expression was associated with better outcomes in PrBC. On the other hand, given that interferons (IFNs) may also trigger immune suppressive mechanisms in cancer cells, the activation of type I IFNs encoded by IFNA17 and IFNB1 seen in our RNA-seq analysis, combined with the lower frequency of CD4+TILs observed, suggest CD4+ cell suppression as a possible mechanism of immune evasion. Conclusion: PrBC TME is characterized by specific patterns of TILs subpopulations due to the possible activation of type I IFNs and its assessment might help in identifying women at high risk of death and recurrence.

Citation Format: Nicola Fusco, Elham Sajjadi, Konstantinos Venetis, Barbara Buonomo, Concetta Blundo, Massimo Giroda, Eugenia Di Loreto, Giovanna Scarfone, Stefano Ferrero, Paolo Veronesi, Viviana E. Galimberti, Massimo Barberis, Giuseppe Viale, Elena Guerini-Rocco, Fedro A. Peccatori. Tumor microenvironment characteristics and prognosis in breast cancer during pregnancy: The role of differentially expressed immune-related genes [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 P4-07-02.

Abstract P3-18-08: Feasibility and safety of breast-conserving surgery in early-stage breast cancers during the first trimester of pregnancy

Background: Breast cancer is the most common malignancy occurring during gestation and should be managed with the same protocols as for young non-pregnant women. In early-stage breast cancer during pregnancy (PrBC), breast-conserving surgery (BCS) with delayed radiation therapy (RT) is a reasonable alternative to radical mastectomy. Regrettably, no specific and widely adopted guidelines on the surgical management of these patients are available. In this study, we investigated the feasibility and safety of BCS during the first trimester of pregnancy in women with early-stage PrBC. Method: The first trimester was defined as 12 weeks and 6 days after the first day of the last menstruation. As for internal protocols, the surgical strategy for PrBC followed the same conservative-oriented schemes applied for nonpregnant patients. Only women with early-stage PrBC treated with BCS during pregnancy followed by planned RT to the whole breast after delivery were included. Exclusion criteria were i) clinical diagnosis or suspicion of inflammatory breast cancer; ii) multicentric disease; iii) diffuse malignant microcalcifications on mammography; iv) previous; v) connective tissue disease, and vi) syndromic breast cancers. All cases underwent central pathological review at the Pathology Department of the European Institute of Oncology. The primary outcome was the isolated local recurrence (ILR). Results: Among 168 PrBC patients, 67 (39.9%) were diagnosed during the first trimester of gestation. Of these, 30 patients (age range, 23-43 years; median=36 years; gestational age, 2-12 weeks; median=7 weeks; median follow-up time=6.5 years) met the inclusion criteria. None of the patients included in this study experienced perioperative surgical complications. No ILR was observed within three months (n=30), 1 year (n=27), and 5 years (n=18) after surgery. The 5-year overall survival rate for all patients was 97% (n=29/30). Four patients experienced ILR or new carcinomas after 6-13 years. These patients are still alive and disease-free after 14-17 years of follow-up. Discussion: In our study, both adjuvant endocrine therapy and anti-HER2 treatment were postponed after delivery. Local recurrences/second primary tumors were observed in 4 out of 30 patients treated with BCS. Given that patient #4 did not receive postoperative RT, but an after-delivery mastectomy for preoperative diagnostic underestimation during pregnancy, this case does not represent a post-BCS recurrence. On the other hand, cases #1-3 could be considered real relapses. Two of these tumors occurred in patients that underwent CT during pregnancy, in which the interval between the end of systemic therapies and the onset of RT was not influenced by the pregnancy. In a single patient (not eligible for systemic treatment in pregnancy), the RT was performed with a longer interval than the usual one of the non-pregnant patients. Survival was not affected by local relapse, underlining the efficacy of salvage treatment.Conclusion: The findings of this study suggest that BCS in the first trimester of pregnancy can be considered reasonably safe for both mother and the child. Mammography should be mandatory in all patients for whom conservative surgery is recommended. Given that the availability of data concerning PrBC and its treatment is scarce and heterogeneous, multicentric studies are warranted.

Citation Format: Nicola Fusco, Concetta Blundo, Massimo Giroda, Elham Sajjadi, Konstantinos Venetis, M. Cristina Leonardi, Elisa Vicini, Luca Despini, Claudia F. Rossi, Letterio Runza, Eugenia Di Loreto, Giovanna Scarfone, Elena Guerini-Rocco, Giuseppe Viale, Paolo Veronesi, Barbara Buonomo, Fedro A. Peccatori, Viviana E. Galimberti. Feasibility and safety of breast-conserving surgery in early-stage breast cancers during the first trimester of pregnancy [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 P3-18-08.

Combined analysis of PTEN, HER2, and hormone receptors status: remodeling breast cancer risk profiling

BACKGROUND

Phosphatase and tensin homolog (PTEN) loss is associated with tumorigenesis, tumor progression, and therapy resistance in breast cancer. However, the clinical value of PTEN as a biomarker in these patients is controversial. We sought to determine whether the benefit of traditional biomarkers testing is improved by the analysis of PTEN status for the identification of high-risk breast cancer.

METHODS

A cohort of 608 patients with breast cancer was included in this study. Based on the expression on the neoplastic cells compared to the normal internal controls by immunohistochemistry (IHC), cases were classified as PTEN-low (PTEN-L) or PTEN-retained (PTEN-WT). The former constituted the study group, while the latter the control group. Analysis of gene expression was performed on publicly available genomic data and included 4265 patients from the METABRIC and MSK cohorts retrieved from cBioPortal. The Shapiro-Wilk test was used to analyze the normal distributions of continuous variables. Relationships between PTEN status and the clinicopathologic and molecular features of the patient population were assessed using Fisher's exact test or Chi-squared/Wilcoxon rank-sum test. Survival curves were built according to the Kaplan-Meier method.

RESULTS

Alteration in PTEN status was significantly different at protein and gene levels, where the reduced protein expression was observed in 280/608 cases (46.1%) from our group, while genetic aberrations in only 315/4265 (7.4%) cases of the METABRIC and MSK cohorts. PTEN-L tumors were significantly enriched for hormone receptors (HR) and HER2 negativity (n = 48, 17.1%) compared to PTEN-WT tumors (n = 22, 6.7%; p = 0.0008). Lack of HR with or without HER2 overexpression/amplification was significantly associated with worse overall survival (OS) in PTEN-L but not in PTEN-WT breast cancers (p < .0001). Moreover, PTEN-L protein expression but not gene alterations was related to the outcome, in terms of both OS and disease-free survival (p = 0.002).

CONCLUSIONS

The combined analysis of PTEN, HER2, and HR status offers relevant information for a more precise risk assessment of patients with breast cancer.

Early Breast Cancers During Pregnancy Treated With Breast-Conserving Surgery in the First Trimester of Gestation: A Feasibility Study

Breast cancer is the most common malignancy occurring during gestation. In early-stage breast cancer during pregnancy (PrBC), breast-conserving surgery (BCS) with delayed RT is a rational alternative to mastectomy, for long considered the standard-of-care. Regrettably, no specific guidelines on the surgical management of these patients are available. In this study, we investigated the feasibility and safety of BCS during the first trimester of pregnancy in women with early-stage PrBC. All patients with a diagnosis of PrBC during the first trimester of pregnancy jointly managed in two PrBC-specialized Centers were included in this study. All patients underwent BCS followed by adjuvant radiotherapy to the ipsilateral breast after delivery. Histopathological features and biomarkers were first profiled on pre-surgical biopsies. The primary outcome was the isolated local recurrence (ILR). Among 168 PrBC patients, 67 (39.9%) were diagnosed during the first trimester of gestation. Of these, 30 patients (age range, 23-43 years; median=36 years; gestational age, 2-12 weeks; median=7 weeks; median follow-up time=6.5 years) met the inclusion criteria. The patients that were subjected to radical surgery (n=14) served as controls. None of the patients experienced perioperative surgical complications. No ILR were observed within three months (n=30), 1 year (n=27), and 5 years (n=18) after surgery. Among the study group, 4 (12.3%) patients experienced ILR or new carcinomas after 6-13 years, the same number (n=4) had metastatic dissemination after 3-7 years. These patients are still alive and disease-free after 14-17 years of follow-up. The rate of recurrences and metastasis in the controls were not significantly different. The findings provide evidence that BCS in the first trimester PrBC is feasible and reasonably safe for both the mother and the baby.

Micropapillary Bladder Cancer Metastatic to the Breast: A Case Report and Brief Literature Review

BACKGROUND

Bladder cancer (BC) usually metastasizes to the lymph nodes, bone, lung, liver and peritoneum, but rarely in the breast.

CASE REPORT

We present a case of a 66-year-old female diagnosed with a massive bladder tumor, who presented a right mammary nodule after neo-adjuvant chemotherapy. A biopsy of the nodule did not permit a definite diagnosis of metastatic spread, which was confirmed by excision of the nodule. In the literature, we found only 7 other similar cases of BC metastasis to the breast. Currently, a non-invasive method for differentiating a breast metastasis from primary cancer is lacking, although there are some clinical and radiological aspects that may help the diagnosis. Histological examination provides diagnostic certainty.

CONCLUSION

Breast metastases from BC are unusual and consequently difficult to identify without non-invasive tools. Clinical history and histological study play a pivotal role in determining the correct diagnosis.

Abstract P2-05-03: Integrated analysis of mismatch repair, PD-L1, and immune microenvironment status in pregnancy-associated breast cancers

Introduction: Breast cancer (BC) occurring during gestation or lactation is rare, yet highly challenging under both biological and clinical standpoints. This condition, referred to as pregnancy-associated (PA) BC (PABC), shows enrichment in mismatch repair (MMR) deficiency mutational signature, higher expression of immune-checkpoint genes, and less tumor-infiltrating lymphocytes (TILs) compared to non-PA BCs. Despite these insights, no comprehensive data on MMR protein status, immune checkpoints, and immune microenvironment are currently available for these tumors. The aim of this study was to characterize the MMR status and immunologic milieu of PABC.

Methods: Among a multi-Institutional database comprising 142 PABCs, we conducted a comparative analysis of a cohort of PABC (n=29) and a control group of age-matched non-PA BCs (n=74). Distinct areas of each tumor and the corresponding normal breast tissue were incorporated into a tissue microarray (4-6 cores per case, mean 4.5). For all cases, both stromal and intratumoral TILs were quantified according to the International TILs Working Group recommendations. Representative slides were subjected to immunohistochemical (IHC) analysis of the MMR proteins (i.e. MLH1, MSH2, MSH6, and PMS2), programmed death-ligand 1 (PD-L1), CD4, and CD8. Cases were classified as MMR-proficient (pMMR), MMR-deficient (dMMR), and, when the protein was expressed only in a part of the tumor, MMR-heterogeneous (hMMR). PD-L1 expression was evaluated separately in the tumor cells, stromal TILs, and intratumoral TILs. Finally, the relative proportion of CD4+ and CD8+ cells was assessed in both stromal and intratumoral TILs.

Results: The study group included 4 (14%) Luminal A, 10 (35%) Luminal B, 4 (14%) non-luminal HER2+, and 11 (37%) triple-negative (TN) PABCs. Taken together, both the dMMR and hMMR status were more common in PABCs than in non-PA BC (n=3/29, 19% vs. n=6/74, 8% and n=7/29, 24% vs. 14/74, 19%, respectively). Specifically, dMMR was seen in Luminal A (n=2, 50%) and in TN (n=1, 9%) PABCs. Conversely, in non-PA BCs, all Luminal A (n=15, 100%) were pMMR, while 5/45(11%) Luminal B and 1/13 (7%) TNBC were dMMR. Despite no differences were observed in intratumoral TILs, PABCs showed significantly higher levels of stromal TILs (p=0.01). Compared to the control group, PD-L1 expression in PABCs was significantly higher in the tumor cells and in stromal TILs (p&lt;0.01) but not in intratumoral TILs. Hence, 9 (31%) PABCs were PD-L1+, with tumor proportion scores (TPS) ranging from 2 to 10 (mean 5), while only 4 (5%) non-PA BCs were PD-L1+ (TPS 2-20, mean 8)(p=0.01). The expression of PD-L1 in stromal TILs was higher in PABCs (n=9, 31%) than in the controls (n=19, 26%)(p=0.005). In Luminal tumors, both the CD4+ and CD8+ populations were more represented than in non-PA BCs (p=0.01), while in TNBC only the relative proportion of CD4+ cells was significantly higher (p=0.02).

Discussion: This study is the first to investigate the immune response alongside the MMR status by IHC in PABCs. Our findings broaden the understanding of the immunobiology underpinning PABC, suggesting that in these tumors i) MMR protein alterations occur at higher frequency than in non-PA BCs; ii) the tumor cells and tumor microenvironment may be capable to suppress the adaptive arm of immune system through the expression of PD-L1; and iii) lymphocytes located at the periphery rather than those inside of the tumor are likely to be implicated in the immune modulation.

Conclusion: The MMR system and immune microenvironment may play a consistent role in the natural history of PABCs. An intimate knowledge of the multifaceted interplay between tumor and tumor immune microenvironment is likely to unveil clinically relevant mechanisms that may have a positive net health impact for women with BC during gestation or lactation.

Citation Format: Nicola Fusco, Elena Guerini-Rocco, Barbara Buonomo, Roberto Croci, Caterina Fumagalli, Gianluca Lopez, Giorgio A Croci, Letterio Runza, Elham Sajjadi, Concetta Blundo, Luca Despini, Massimo Giroda, Viviana E Galimberti, Paolo Veronesi, Massimo Barberis, Stefano Ferrero, Giovanna Scarfone, Silvano Bosari, Giuseppe Viale, Fedro Peccatori. Integrated analysis of mismatch repair, PD-L1, and immune microenvironment status in pregnancy-associated breast cancers [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-05-03.

Integrating Augmented Reality Tools in Breast Cancer Related Lymphedema Prognostication and Diagnosis

Breast cancer related lymphedema (BCRL) is a detrimental condition characterized by fluid accumulation in the upper limb in breast cancer patients subjected to axillary surgery and/or radiations. Its etiology is multifactorial and include also tumor-specific pathological features, such as lymphovascular invasion (LVI) and extranodal extension (ENE). To date, no widely employed guidelines for the early diagnosis of BCRL are available. Here, we illustrate a protocol for a digitally assisted BCRL assessment using a 3D laser scanner (3DLS) and a tablet computer. It has been specifically optimized in a discovery cohort of high-risk breast cancer patients. This study provides a proof-of-principle that augmented reality tools, such as 3DLS, can be incorporated into the clinical workup of BCRL to allow for a precise, reproducible, reliable, and cheap diagnosis.

Abstract P2-08-21: Mismatch repair protein loss is a prognostic and predictive biomarker in breast cancers regardless of microsatellite instability

Despite the approval of pembrolizumab in all tumors showing mismatch-repair (MMR) deficiency and/or microsatellite instability (MSI), there are currently no companion diagnostics for MMR status assessment in breast cancer. Here, we sought to define the diagnostic and prognostic role of MMR and MSI testing in breast cancer patients.

We subjected 444 breast cancers to MMR immunohistochemistry (IHC) and MSI analysis. Cases were classified as MMR-proficient (pMMR), MMR-deficient (dMMR), and MMR-heterogeneous (hMMR) based on the loss of immunoreactivity; MSI was defined by the instability in the five indicators recommended by the National Cancer Institute for endometrial and colorectal cancers. Correlation of MMR status with patients' survival was assessed using the Kaplan-Meier estimator.

In 75 patients (17%) the loss of MMR proteins was homogeneous, classified as dMMR, while 55 cases (12%) were hMMR. The prevalence of cancers with loss of the MMR proteins was homogeneous across ER+ breast cancers (15-19% for dMMR and 10-18% for hMMR tumors). The level of overlap between IHC and MSI analysis was 9% (p&lt;0.0001). Among ER+/HER2- carcinomas, pMMR and hMMR patients displayed better survival rates (p=0.008). In chemo-treated ER-/HER2- breast cancers, the dMMR status was a marker of good prognosis (p&lt;0.001).

Our study documents the clinical impact of MMR testing in a large series of breast cancers, using the most commonly adopted diagnostic tools and criteria. We show that MMR protein loss is a rather common event in breast cancer and has a remarkable degree of intra-tumor heterogeneity, therefore making the analysis of a small area of the tumor, or a small biopsy, of little clinical value. Our investigation supports the concept that MSI occurs rarely in breast cancer and demonstrate that this condition is restricted to a minority of tumors with MMR protein loss. These data suggest that MMR IHC and MSI analysis should not be considered as interchangeable tests in the diagnostic workup of breast carcinomas. Finally, our observations indicate that the complete loss of at least one of the MMR proteins assessed by IHC is able to identify high-risk ER+/HER2- breast cancers that can potentially benefit from pembrolizumab therapy, whereas first-line chemotherapy shows comparatively good results in dMMR ER-/HER2- breast cancers.

Citation Format: Fusco N, Lopez G, Corti C, Pesenti C, Colapietro P, Ercoli G, Gaudioso G, Faversani A, Gambini D, Despini L, Blundo C, Vaira V, Miozzo M, Ferrero S, Bosari S. Mismatch repair protein loss is a prognostic and predictive biomarker in breast cancers regardless of microsatellite instability [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-21.

Breast Cancer Systemic Treatments and Upper Limb Lymphedema: A Risk-Assessment Platform Encompassing Tumor-Specific Pathological Features Reveals the Potential Role of Trastuzumab

Breast cancer related lymphedema (BCRL) is frequent but strategies for an individualized risk assessment are lacking. We aimed to define whether tumor-specific pathological features, coupled with clinical and therapeutic data, could help identify patients at risk. Data from 368 patients with node-positive breast cancers were retrospectively collected, including 75 patients with BCRL (0.4⁻25.6 years follow-up). BCRL was assessed during the standard follow-up oncology visits using the circumferential measurement. Clinicopathologic and therapeutic factors associated with BCRL were integrated into a Cox proportional hazards regression model. Lymphovascular invasion (LVI) was more common in BCRL patients (n = 33, 44% vs. n = 85, 29%, p = 0.01), akin extra nodal extension (ENE) of the metastasis (n = 57, 76% vs. n = 180, 61%, p = 0.02). Sentinel lymph node excision without axillary dissection and extra-axillary radiotherapy were BCRL-unrelated. A higher number of BCRL-positive patients were treated with taxane-based chemotherapy with or without trastuzumab, compared to BCRL-negative patients (p < 0.01). Treatment with trastuzumab and/or taxanes, adjusted for systemic infections, laterality, therapy, and pathological features (i.e., LVI and ENE), had a significant impact in BCRL-free survival (p < 0.01). This work offers new insights on BCRL risk stratification, where the integration of clinical, therapeutic, and tumor-specific pathological data suggests a possible role of anti-human epidermal growth factor receptor 2 (HER2) therapy in BCRL pathogenesis.

Mismatch Repair Protein Loss as a Prognostic and Predictive Biomarker in Breast Cancers Regardless of Microsatellite Instability

Background

Breast cancers that harbor mismatch-repair (MMR) deficiency and/or microsatellite instability (MSI) might be sensitive to immune checkpoint blockade, but there are currently no specific guidelines for assessing MMR status in breast cancer. Here, we sought to define the clinical value of MMR immunohistochemistry (IHC) and MSI analysis in breast cancers.

Methods

We subjected 444 breast cancers to MMR IHC and MSI analysis. Cases were classified as MMR-proficient (pMMR), MMR-deficient (dMMR), and MMR-heterogeneous (hMMR) based on the loss of immunoreactivity; MSI was defined by instability in the five indicators recommended by the National Cancer Institute for endometrial and colorectal cancers. Correlation of MMR status with patients' survival was assessed using the Kaplan-Meier estimator. Statistical tests were two-sided.

Results

Loss of MMR proteins was homogeneous (dMMR) in 75 patients (17%) and heterogeneous (hMMR) in 55 (12%). Among luminal breast cancers, there were similar frequencies of dMMR and hMMR tumors. Overall, the rate of discrepancy between IHC and MSI analysis was high (91%). Women with Luminal B-like dMMR carcinomas (n = 44) showed shorter overall survival (median = 77 months, range = 0-115 months) than those with pMMR (n = 205) or hMMR (n = 35) tumors (median = 84 months, range = 0-127 months) (P = .008). On the contrary, patients with estrogen receptor-negative breast cancers treated with chemotherapy lived longer in cases of dMMR (n = 9) than pMMR (n = 33) or hMMR (n = 7) tumors, with 87 months of median survival (range = 73-123 months) for the former compared with 79 months (range = 8-113 months) for the latter two categories (P < .001).

Conclusions

Immunohistochemistry and MSI are not interchangeable tests in breast carcinomas. MMR protein loss is a more common event than MSI and shows intra-tumor heterogeneity. MMR IHC allows the identification of clinically relevant subclasses of breast cancer patients, provided that multiple areas of the tumor are analyzed.

Building Up a High-throughput Screening Platform to Assess the Heterogeneity of HER2 Gene Amplification in Breast Cancers

Targeted therapies against the human epidermal growth factor receptor 2 (HER2) have radically changed the outcome of patients with HER2-positive breast cancers. However, a minority of cases displays a heterogeneous distribution of HER2-positive cells, which generates major clinical challenges. To date, no reliable and standardized protocols for the characterization and quantification of HER2 heterogeneous gene amplification in large cohorts have been proposed. Here, we present a high-throughput methodology to simultaneously assess the HER2 status across different topographic areas of multiple breast cancers. In particular, we illustrate the laboratory procedure to construct enhanced tissue microarrays (TMAs) incorporating a targeted mapping of the tumors. All TMA parameters have been specifically optimized for the silver in situ hybridization (SISH) of formalin-fixed paraffin-embedded (FFPE) breast tissues. Immunohistochemical analysis of the prognostic and predictive biomarkers (i.e., ER, PR, Ki67, and HER2) should be performed using automated procedures. A customized SISH protocol has been implemented to allow a high-quality molecular analysis across multiple tissues that underwent different fixation, processing, and storage procedures. In this study, we provide a proof-of-principle that specific DNA sequences could be localized simultaneously in distinct topographic areas of multiple and heterogeneously processed breast cancers using an efficient and cost-effective method.

A selective egocentric topographical working memory deficit in the early stages of Alzheimer's disease: a preliminary study

The aim of this study was to determine whether an egocentric topographical working memory (WM) deficit is present in the early stages of Alzheimer's disease (AD) with respect to other forms of visuospatial WM. Further, we would investigate whether this deficit could be present in patients having AD without topographical disorientation (TD) signs in everyday life assessed through an informal interview to caregivers. Seven patients with AD and 20 healthy participants performed the Walking Corsi Test and the Corsi Block-Tapping Test. The former test requires memorizing a sequence of places by following a path and the latter is a well-known visuospatial memory task. Patients with AD also performed a verbal WM test to exclude the presence of general WM impairments. Preliminary results suggest that egocentric topographical WM is selectively impaired, with respect to visuospatial and verbal WM, even without TD suggesting an important role of this memory in the early stages of AD.

When, where, and how the corpus callosum changes in MCI and AD: a multimodal MRI study

BACKGROUND

The corpus callosum (CC) has been shown to be susceptible to atrophy in Alzheimer disease (AD) as a correlate of wallerian degeneration or retrogenesis. However, when and where these 2 mechanisms intervene is still unclear.

METHODS

In 3 memory clinics, we recruited 38 patients with amnestic mild cognitive impairment (MCI), 38 patients with mild AD, and 40 healthy controls (HC). Combining voxel-based morphometry and diffusion tensor imaging, we investigated CC white matter (WM) density and fractional anisotropy (FA), radial diffusivity (DR), and axial diffusivity (DA).

RESULTS

Compared with HC, patients with amnestic MCI showed reduced WM density in the anterior CC subregion; however, FA, DR, and DA did not differ between the 2 groups. Significant changes were found in patients with mild AD compared with HC in the anterior and posterior CC regions. These differences were evident in both voxel-based morphometry and diffusion tensor imaging analyses. Specifically, we found reduced callosal WM density in the genu, posterior body, and splenium; decreased FA and increased DR in the anterior CC subregion; and increased DA, with no difference in the FA, in the posterior CC subregion.

CONCLUSIONS

Callosal changes are already present in patients with amnestic mild cognitive impairment (MCI) and mild Alzheimer disease (AD). The precocious involvement of the anterior callosal subregion in amnestic MCI extends to posterior regions in mild AD. Two different mechanisms might contribute to the white matter changes in mild AD: wallerian degeneration in posterior subregions of the corpus callosum (suggested by increased axial diffusivity without fractional anisotropy modifications) and a retrogenesis process in the anterior callosal subregions (suggested by increased radial diffusivity without axial diffusivity modifications).

Surgical treatment of the distal anterior cerebral artery aneurysms

A series of eleven patients with aneurysms of distal anterior cerebral artery, microsurgically operated and submitted to accurate neuropsychological testing, is reviewed. Of these, ten patients had an aneurysm at the bifurcation of distal ACA into pericallosal and callosomarginal branches and only one patient had an aneurysm at the beginning of the fronto-polar artery. All our patients were operated by an interhemispheric approach, that was associated in 3 cases to a pterional approach in order to clip a second aneurysm in other location. The postoperative grade was satisfactory in any of the eleven patients. The aneurysms of distal ACA may be surgically obliterated through a variety of approaches but the exposure via the interhemispheric fissure is used by many neurosurgeons. In our experience the interhemispheric approach allows the exposure of feeding artery and the control of proximal vessel without morbidity. Some authors have modified the interhemispheric approach to improve, in their opinion, surgical exposure, introducing partial resection of anterior portion of corpus callosum, used, by them, especially for the aneurysms just beneath the genu of corpus callosum. Although resection of the anterior 2.5 cm of the corpus callosum can be performed without causing any neurological deficit, as reported by the same authors, the use of this technique might not be necessary. The present paper deals with current surgical techniques and their modification for the treatment of distal anterior cerebral artery (ACA) aneurysms.

Perception of ambiguous figures after focal brain lesions

Forty patients with unilateral frontal or posterior brain damage and 20 normal control subjects were tested on an ambiguous figures task (AFT). For each figure they were asked to recognize both ambiguous images. Subjects failing to recognize the second aspect of an ambiguous figure were prompted with the name of the image not yet perceived. The Wisconsin Card Sorting Test (WCST) was also administered to all subjects. Frontal patients exhibited greater difficulty in shifting from one aspect of an ambiguous figure to the other than did patients with more posterior lesions and control subjects. In addition, frontal-posterior and control differences were highly significant for number of prompts given. For the frontal patients, significant correlations were found between the number of prompts on the AFT and the number of perseverative errors on the WCST. Poor performance on the AFT can be considered as a "frontal lobe sign" of perceptual persevation.

Avoidance conditioning in amnesia: a single case experimental study

We present a single case study of avoidance conditioning in a seriously amnesic patient with bilateral ischemic lesions of the brain. A four-path maze was used for conditioning. The procedure consisted in an aversive stimulus that the patient received every time he traced one of the four maze-paths connected to an electric shock generator with a stylus. Using a single case experimental design A-B-A, we found that the patient learned to avoid the path connected to the electric shock, although he never showed awareness of this. Our study confirms once again that conditioning is one of the residual learning capabilities in amnesic patients. Different neural systems are probably involved in conditioning processes.