Prediction of pathologic complete response after single-dose MR-guided partial breast irradiation in low-risk breast cancer patients: the ABLATIVE-2 trial-a study protocol

BACKGROUND

Partial breast irradiation (PBI) is standard of care in low-risk breast cancer patients after breast-conserving surgery (BCS). Pre-operative PBI can result in tumor downstaging and more precise target definition possibly resulting in less treatment-related toxicity. This study aims to assess the pathologic complete response (pCR) rate one year after MR-guided single-dose pre-operative PBI in low-risk breast cancer patients.

METHODS

The ABLATIVE-2 trial is a multicenter prospective single-arm trial using single-dose ablative PBI in low-risk breast cancer patients. Patients ≥ 50 years with non-lobular invasive breast cancer ≤ 2 cm, grade 1 or 2, estrogen receptor-positive, HER2-negative, and tumor-negative sentinel node procedure are eligible. A total of 100 patients will be enrolled. PBI treatment planning will be performed using a radiotherapy planning CT and -MRI in treatment position. The treatment delivery will take place on a conventional or MR-guided linear accelerator. The prescribed radiotherapy dose is a single dose of 20 Gy to the tumor, and 15 Gy to the 2 cm of breast tissue surrounding the tumor. Follow-up MRIs, scheduled at baseline, 2 weeks, 3, 6, 9, and 12 months after PBI, are combined with liquid biopsies to identify biomarkers for pCR prediction. BCS will be performed 12 months after radiotherapy or after 6 months, if MRI does not show a radiologic complete response. The primary endpoint is the pCR rate after PBI. Secondary endpoints are radiologic response, toxicity, quality of life, cosmetic outcome, patient distress, oncological outcomes, and the evaluation of biomarkers in liquid biopsies and tumor tissue. Patients will be followed up to 10 years after radiation therapy.

DISCUSSION

This trial will investigate the pathological tumor response after pre-operative single-dose PBI after 12 months in patients with low-risk breast cancer. In comparison with previous trial outcomes, a longer interval between PBI and BCS of 12 months is expected to increase the pCR rate of 42% after 6-8 months. In addition, response monitoring using MRI and biomarkers will help to predict pCR. Accurate pCR prediction will allow omission of surgery in future patients.

TRIAL REGISTRATION

The trial was registered prospectively on April 28th 2022 at clinicaltrials.gov (NCT05350722).

Characterizing the Bone Marrow Environment in Advanced-Stage Myelofibrosis during Ruxolitinib Treatment Using PET/CT and MRI: A Pilot Study

Current diagnostic criteria for myelofibrosis are largely based on bone marrow (BM) biopsy results. However, these have several limitations, including sampling errors. Explorative studies have indicated that imaging might form an alternative for the evaluation of disease activity, but the heterogeneity in BM abnormalities complicates the choice for the optimal technique. In our prospective diagnostic pilot study, we aimed to visualize all BM abnormalities in myelofibrosis before and during ruxolitinib treatment using both PET/CT and MRI. A random sample of patients was scheduled for examinations at baseline and after 6 and 18 months of treatment, including clinical and laboratory examinations, BM biopsies, MRI (T1-weighted, Dixon, dynamic contrast-enhanced (DCE)) and PET/CT ([¹⁵O]water, [¹⁸F]NaF)). At baseline, all patients showed low BM fat content (indicated by T1-weighted MRI and Dixon), increased BM blood flow (as measured by [¹⁵O]water PET/CT), and increased osteoblastic activity (reflected by increased skeletal [¹⁸F]NaF uptake). One patient died after the baseline evaluation. In the others, BM fat content increased to various degrees during treatment. Normalization of BM blood flow (as reflected by [¹⁵O]water PET/CT and DCE-MRI) occurred in one patient, who also showed the fastest clinical response. Vertebral [¹⁸F]NaF uptake remained stable in all patients. In evaluable cases, histopathological parameters were not accurately reflected by imaging results. A case of sampling error was suspected. We conclude that imaging results can provide information on functional processes and disease distribution throughout the BM. Differences in early treatment responses were especially reflected by T1-weighted MRI. Limitations in the gold standard hampered the evaluation of diagnostic accuracy.

Abstract P3-02-11: Towards a new standard for staging: A comparative study of [18F]FES PET/CT vs [18F]FDG PET/CT in patients with clinical stage II/III and locoregional recurrent estrogen receptor positive breast cancer

Introduction: Accurate staging of patients with locally advanced breast cancer or locoregional recurrent (LRR) breast cancer is essential for providing a tailored treatment. According to current guidelines, staging is preferably done with positron emission tomography (PET) using 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG), combined with diagnostic computed tomography (CT). Previous studies suggest that [18F]FDG PET might underperform in patients with grade 1-2, estrogen receptor positive (ER+) breast cancer as these tumors are often metabolically less active than other subtypes of breast cancer. Thus, there is a need to improve current diagnostics for this population. 16α-[18F]-fluoro-17β-estradiol ([18F]FES), radioactive labeled estradiol, has emerged as a powerful imaging tool for in vivo visualization of ER+ lesions. The aim of this study was to investigate whether [18F]FES PET/CT improves staging of patients with clinical stage II/III or LRR ER+ breast cancer, compared to [18F]FDG PET/CT. Methods: Patients with clinical stage II/III or LRR 1-2, ER+ breast cancer were included in this prospective multicenter clinical trial (NCT03726931). All patients underwent a [18F]FES PET/CT and a [18F]FDG PET/CT scan. Both PET scans were visually assessed, independently of each other. Visually suspect lesions for malignancy were verified pathologically (by biopsy or fine needle aspiration) or by conventional imaging (mammography, ultrasound, magnetic resonance imaging, CT). The stage of the disease was determined twice in a multidisciplinary team, based on conventional diagnostics (conventional imaging and pathology) and [18F]FDG PET/CT or [18F]FES PET/CT, respectively. Semi-quantitative PET parameters, standardized uptake values (SUVs) and tumor-to-blood ratios (TBRs), were obtained by defining volumes of interest in the aorta ascendens and in suspect tumor lesions. These PET parameters were correlated with various pathological features, such as histological subtype, grade and ER, progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) expression. Results: A total of 40 patients were included. On patient level, the sensitivity of [18F]FES PET/CT and [18F]FDG PET/CT to detect ER+ disease was 87.5% and 82.5%, respectively. [18F]FES PET/CT correctly determined the stage in 34/40 patients (85.0%) whereas [18F]FDG PET/CT correctly determined the stage in 29/40 patients (72.5%). [18F]FES PET/CT correctly changed the stage in 8/40 patients (20.0%) with upstaging in 6 patients and downstaging in 2 patients, compared to [18F]FDG PET/CT. On lesion level, a total of 140 suspect lesions were analyzed: 82 lesions were pathologically verified whereas 58 were radiographically verified. The sensitivity for lesion detection on [18F]FES PET/CT and [18F]FDG PET/CT was 90.6% and 77.3%, respectively. [18F]FES PET/CT identified more lesions correctly: 120/140 (85.7%) lesions vs 103/140 (73.6%) on [18F]FES PET/CT vs [18F]FDG PET/CT, respectively. [18F]FES PET/CT also missed less lesions (12/140, 8.6%) compared to [18F]FDG PET/CT (29/140, 20.7%). [18F]FES SUVmax, SUVmean, SUVpeak and TBR correlated with ductal subtype and percentage of PR expression (p <0.05, positive correlation). Conclusion: [18F]FES PET/CT improves disease staging in patients with stage II/III and LRR grade 1-2, ER+ breast cancer, compared to [18F]FDG PET/CT. This is in line with the ability of the tracer to identify malignant lesions more accurately in this patient population and supports further development of [18F]FES for staging grade 1-2, ER+ breast cancer.

Citation Format: Ramsha Iqbal, Emma C Bonjer, Annette van Zweeden, Lemonitsa H Mammatas, Jaap JM Teunissen, Jan Booij, Gwen MP Diepenhorst, Laura Schijf, Susanne van der Velde, Katya Duvivier, Ellis Barbé, Daniela E Oprea-Lager, Catharina W Menke-van der Houven van Oordt. Towards a new standard for staging: A comparative study of [18F]FES PET/CT vs [18F]FDG PET/CT in patients with clinical stage II/III and locoregional recurrent estrogen receptor positive breast cancer [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 P3-02-11.

Incidence of testicular cancer in trans women using gender-affirming hormonal treatment: a nationwide cohort study

Objective

To assess the incidence of testicular cancer in trans women (male sex assigned at birth, female gender identity) using gender‐affirming hormonal treatment.

Patients and Methods

Data of trans women starting hormonal treatment at our gender identity clinic between 1972 and 2017 were linked to the national pathology database to obtain testicular cancer diagnoses. The standardised incidence ratio (SIR) was calculated using the number of observed testicular cancer cases in our cohort and the number of expected cases based on age‐specific Dutch incidence rates. Subgroup analyses were performed in testicular tissues sent for histopathological analysis at the time of bilateral orchidectomy, and when follow‐up exceeded 5 years.

Results

The cohort consisted of 3026 trans women with a median follow‐up time of 2.3 interquartile range (IQR) (1.6–3.7) years. Two testicular cancer cases were identified whilst 2.4 cases were expected (SIR 0.8, 95% confidence interval 0.1–2.8). In addition, one testicular cancer case was encountered in an orchidectomy specimen (0.1%). In the 523 trans women with a follow‐up time of >5 years (median [IQR] 8.9 [6.4–13.9] years), no testicular cancer was observed.

Conclusion

Testicular cancer risk in trans women is similar to the risk in cis men. The testicular cancer cases occurred within the first 5 years after commencing hormonal treatment, and the percentage of cases encountered at the time of bilateral orchidectomy was low. As no testicular cancer was observed in trans women with a long follow‐up period, long‐term hormonal treatment does not seem to increase testicular cancer risk.

Localized Peritumoral AL Amyloidosis Associated With Mantle Cell Lymphoma With Plasmacytic Differentiation

Immunoglobulin light chain (AL) amyloidosis is characterized by the deposition of amyloid fibers derived from pathologic immunoglobulin light chains. Although systemic plasma cell neoplasms are the most common cause of AL amyloidosis, a subset of cases is caused by B-cell lymphoproliferative disorders such as lymphoplasmacytic lymphoma or extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue. Recently, SOX11-negative IGH hypermutated mantle cell lymphoma (MCL) is recognized to show frequent plasmacytic differentiation and indolent clinical course. Here, we report 3 cases of peritumoral AL amyloidosis associated with SOX11-negative MCL. All 3 cases showed cyclin D1 expression by immunohistochemistry and CCND1 translocation as detected by fluorescence in situ hybridization analysis. Peritumoral AL amyloidosis was observed at the biopsy sites in the gastrointestinal tract, a supraclavicular lymph node, and a cervical lymph node, and all presented with marked plasmacytic differentiation of lymphoma cells. None of the cases showed evidence of bone marrow involvement by morphology and immunophenotyping. None of the patients had distant organ involvement with systemic amyloidosis. All 3 patients had an indolent clinical course and are alive with disease at the time of the last follow-up (range: 48 to 74 mo). Our findings show that MCL with plasmacytic differentiation can cause amyloid deposition and CCND1 abnormalities should be performed in all cases of extramedullary AL amyloidosis. Recognition of indolent MCL as a cause of peritumoral AL amyloidosis may have important clinical management implications.

Prostate Cancer Incidence under Androgen Deprivation: Nationwide Cohort Study in Trans Women Receiving Hormone Treatment

CONTEXT

Trans women (male sex assigned at birth, female gender identity) mostly use antiandrogens combined with estrogens and can subsequently undergo vaginoplasty including orchiectomy. Because the prostate remains in situ after this procedure, trans women are still at risk for prostate cancer.

OBJECTIVE

To assess the incidence of prostate cancer in trans women using hormone treatment. The incidence of prostate cancer in trans women using hormone treatment.

DESIGN

In this nationwide retrospective cohort study, data of participants were linked to the Dutch national pathology database and to Statistics Netherlands to obtain data on prostate cancer diagnosis and mortality.

SETTING

Gender identity clinic.

PARTICIPANTS

Trans women who visited our clinic between 1972 and 2016 and received hormone treatment were included.

MAIN OUTCOME MEASURES

Standardized incidence ratios (SIRs) were calculated using the number of observed prostate cancer cases in our cohort and the number of expected cases based on age-specific incidence numbers from the Netherlands Comprehensive Cancer Organization.

RESULTS

The study population consisted of 2281 trans women with a median follow-up time of 14 years (interquartile range 7-24), and a total follow-up time of 37 117 years. Six prostate cancer cases were identified after a median 17 years of hormone treatment. This resulted in a lower prostate cancer risk in trans women than in Dutch reference males (SIR 0.20, 95% confidence interval 0.08-0.42).

CONCLUSIONS

Trans women receiving androgen deprivation therapy and estrogens have a substantially lower risk for prostate cancer than the general male population. Our results support the hypothesis that androgen deprivation has a preventive effect on the initiation and development of prostate cancer.

[Prioritising breast cancer care during the corona crisis]

Over the past few months, regular care has been postponed where possible in order to increase the healthcare capacity for COVID-19 patients. The pressure imposed on the healthcare system by the new coronavirus has led to the need for the prioritising of breast cancer care. Several professional scientific and medical organisations have published proposals to prioritise oncological care. Due to the poor prognosis, care for patients with progressive disease during neoadjuvant systemic therapy and a triple negative, may not be postponed. In certain groups of patients, including those with ductal carcinoma in situ or an endocrine sensitive tumour, treatment may be postponed or modified, although with certain reservations.At the initiative of the NationaalBorstkankerOverleg Nederland, prospective data are currently being collected in order to gain more insight into the impact of COVID-19 on breast cancer care.

Label-free stimulated Raman scattering imaging reveals silicone breast implant material in tissue

Millions of women worldwide have silicone breast implants. It has been reported that implant failure occurs in approximately a tenth of patients within 10 years, and the consequences of dissemination of silicone debris are poorly understood. Currently, silicone detection in histopathological slides is based on morphological features as no specific immunohistochemical technique is available. Here, we show the feasibility and sensitivity of stimulated Raman scattering (SRS) imaging to specifically detect silicone material in stained histopathological slides, without additional sample treatment. Histology slides of four periprosthetic capsules from different implant types were obtained after explantation, as well as an enlarged axillary lymph node from a patient with a ruptured implant. SRS images coregistered with bright-field images revealed the distribution and quantity of silicone material in the tissue. Fast and high-resolution imaging of histology slides with molecular specificity using SRS provides an opportunity to investigate the role of silicone debris in the pathophysiology of implant-linked diseases.

The molecular genetic make-up of male breast cancer

Male breast cancer (MBC) is extremely rare and accounts for less than 1% of all breast malignancies. Therefore, clinical management of MBC is currently guided by research on the disease in females. In this study, DNA obtained from 45 formalin-fixed paraffin-embedded (FFPE) MBCs with and 90 MBCs (52 FFPE and 38 fresh-frozen) without matched normal tissues was subjected to massively parallel sequencing targeting all exons of 1943 cancer-related genes. The landscape of mutations and copy number alterations was compared to that of publicly available estrogen receptor (ER)-positive female breast cancers (smFBCs) and correlated to prognosis. From the 135 MBCs, 90% showed ductal histology, 96% were ER-positive, 66% were progesterone receptor (PR)-positive, and 2% HER2-positive, resulting in 50, 46 and 4% luminal A-like, luminal B-like and basal-like cases, respectively. Five patients had Klinefelter syndrome (4%) and 11% of patients harbored pathogenic BRCA2 germline mutations. The genomic landscape of MBC to some extent recapitulated that of smFBC, with recurrent PIK3CA (36%) and GATA3 (15%) somatic mutations, and with 40% of the most frequently amplified genes overlapping between both sexes. TP53 (3%) somatic mutations were significantly less frequent in MBC compared to smFBC, whereas somatic mutations in genes regulating chromatin function and homologous recombination deficiency-related signatures were more prevalent. MDM2 amplifications were frequent (13%), correlated with protein overexpression (P = 0.001) and predicted poor outcome (P = 0.007). In conclusion, despite similarities in the genomic landscape between MBC and smFBC, MBC is a molecularly unique and heterogeneous disease requiring its own clinical trials and treatment guidelines.

Second and third harmonic generation microscopy visualizes key structural components in fresh unprocessed healthy human breast tissue

Real-time assessment of excised tissue may help to improve surgical results in breast tumor surgeries. Here, as a step towards this purpose, the potential of second and third harmonic generation (SHG, THG) microscopy is explored. SHG and THG are nonlinear optical microscopic techniques that do not require labeling of tissue to generate 3D images with intrinsic depth-sectioning at sub-cellular resolution. Until now, this technique had been applied on fixated breast tissue or to visualize the stroma only, whereas most tumors start in the lobules and ducts. Here, SHG/THG images of freshly excised unprocessed healthy human tissue are shown to reveal key breast components-lobules, ducts, fat tissue, connective tissue and blood vessels, in good agreement with hematoxylin and eosin histology. DNA staining of fresh unprocessed mouse breast tissue was performed to aid in the identification of cell nuclei in label-free THG images. Furthermore, 2- and 3-photon excited auto-fluorescence images of mouse and human tissue are collected for comparison. The SHG/THG imaging modalities generate high quality images of freshly excised tissue in less than a minute with an information content comparable to that of the gold standard, histopathology. Therefore, SHG/THG microscopy is a promising tool for real-time assessment of excised tissue during surgery.

Breast cancer risk in transgender people receiving hormone treatment: nationwide cohort study in the Netherlands

OBJECTIVE

To investigate the incidence and characteristics of breast cancer in transgender people in the Netherlands compared with the general Dutch population.

DESIGN

Retrospective, nationwide cohort study.

SETTING

Specialised tertiary gender clinic in Amsterdam, the Netherlands.

PARTICIPANTS

2260 adult trans women (male sex assigned at birth, female gender identity) and 1229 adult trans men (female sex assigned at birth, male gender identity) who received gender affirming hormone treatment.

MAIN OUTCOME MEASURES

Incidence and characteristics (eg, histology, hormone receptor status) of breast cancer in transgender people.

RESULTS

The total person time in this cohort was 33 991 years for trans women and 14 883 years for trans men. In the 2260 trans women in the cohort, 15 cases of invasive breast cancer were identified (median duration of hormone treatment 18 years, range 7-37 years). This was 46-fold higher than in cisgender men (standardised incidence ratio 46.7, 95% confidence interval 27.2 to 75.4) but lower than in cisgender women (0.3, 0.2 to 0.4). Most tumours were of ductal origin and oestrogen and progesterone receptor positive, and 8.3% were human epidermal growth factor 2 (HER2) positive. In 1229 trans men, four cases of invasive breast cancer were identified (median duration of hormone treatment 15 years, range 2-17 years). This was lower than expected compared with cisgender women (standardised incidence ratio 0.2, 95% confidence interval 0.1 to 0.5).

CONCLUSIONS

This study showed an increased risk of breast cancer in trans women compared with cisgender men, and a lower risk in trans men compared with cisgender women. In trans women, the risk of breast cancer increased during a relatively short duration of hormone treatment and the characteristics of the breast cancer resembled a more female pattern. These results suggest that breast cancer screening guidelines for cisgender people are sufficient for transgender people using hormone treatment.

A practical cytological approach to the diagnosis of breast-implant associated anaplastic large cell lymphoma

The role of cytopathology in malignant lymphoma is largely restricted to primary screening in patients with lymphadenopathy of unknown causes and evaluation of relapse and transformation during follow-up of patients with known and fully classified malignant lymphoma. Few lymphoma diagnoses fully rely on cytology, although breast-implant associated anaplastic large cell lymphoma is currently the centre of clinical attention. Due to the major attention both in the medical and lay media for the recently substantiated high lymphoma risk in women with breast implants, cytopathology departments now frequently receive seroma fluid aspirates with this specific differential diagnostic consideration. In this review, we discuss clinico-pathological aspects of breast-implant associated anaplastic large cell lymphoma from a cytological point of view and provide guidelines for the processing of aspirates in daily practice and strategies for diagnostic work-up of seroma fluids.

Structure of sticky-hard-sphere random aggregates: The viewpoint of contact coordination and tetrahedra

We study more than 10^{4} random aggregates of 10^{6} monodisperse sticky hard spheres each, generated by various static algorithms. Their packing fraction varies from 0.370 up to 0.593. These aggregates are shown to be based on two types of disordered structures: random regular polytetrahedra and random aggregates, the former giving rise to δ peaks on pair distribution functions. Distortion of structural (Delaunay) tetrahedra is studied by two parameters, which show some similarities and some differences in terms of overall tendencies. Isotropy of aggregates is characterized by the nematic order parameter. The overall structure is then studied by distinguishing spheres in function of their contact coordination number (CCN). Distributions of average CCN around spheres of a given CCN value show trends that depend on packing fraction and building algorithms. The radial dependence of the average CCN turns out to be dependent upon the CCN of the central sphere and shows discontinuities that resemble those of the pair distribution function. Moreover, it is shown that structural details appear when the CCN is used as pseudochemical parameter, such as various angular distribution of bond angles, partial pair distribution functions, Ashcroft-Langreth and Bhatia-Thornton partial structure factors. These allow distinguishing aggregates with the same values of packing fraction or average tetrahedral distortion or even similar global pair distribution function, indicative of the great interest of paying attention to contact coordination numbers to study more precisely the structure of random aggregates.

A nationwide pathology study on surgical margins and excision volumes after breast-conserving surgery: There is still much to be gained

AIM OF THE STUDY

The current study aims to assess margin status in relation to amount of healthy breast tissue resected in breast-conserving surgery (BCS) on a nationwide scale.

METHODS

Using PALGA (a nationwide network and registry of histology and cytopathology in the Netherlands), all patients who underwent BCS for primary invasive carcinoma in 2012-13 were selected (10,058 excerpts). 9276 pathology excerpts were analyzed for a range of criteria including oncological margin status and distance to closest margin, specimen weight/volume, greatest tumor diameter, and with or without localization method. Calculated resection ratios (CRR) were assessed to determine excess healthy breast tissue resection.

RESULTS

Margins for invasive carcinoma and in situ carcinoma combined were tumor-involved in 498 (5.4%) and focally involved in 1021 cases (11.0%) of cases. Unsatisfactory resections including (focally) involved margins and margins ≤ 1 mm were reported in 33.8% of patients. The median lumpectomy volume was 46 cc (range 1-807 cc; SD 49.18) and median CRR 2.32 (range 0.10-104.17; SD 3.23), indicating the excision of 2.3 the optimal resection volume.

CONCLUSION

The unacceptable rate of tumor-involved margins as well as margins ≤ 1 mm in one third of all patients is also achieved at the expense of healthy breast tissue resection, which may carry the drawback of high rates of cosmetic failure. These data clearly suggest the need for improvement in current breast conserving surgical procedures to decrease tumor-involved margin rates while reducing the amount of healthy breast tissue resected.

Anaplastic large-cell lymphoma in women with breast implants

CONTEXT

Recently, we identified 2 patients with anaplastic large T-cell lymphoma (ALCL) negative for tyrosine kinase anaplastic lymphoma kinase (ALK-negative) in the fibrous capsule of silicone breast prostheses, placed for cosmetic reasons. Similar cases have been reported in the literature. Although an increased risk of ALCL in patients with breast prostheses has been speculated, no studies have been conducted so far.

OBJECTIVE

To determine whether ALCL risk is associated with breast prostheses.

DESIGN

A search for all patients with lymphoma in the breast diagnosed in The Netherlands between 1990 and 2006 was performed through the population-based nationwide pathology database. Subsequently, we performed an individually matched case-control study. Conditional logistic regression analysis was performed to estimate the relative risk of ALCL associated with breast prostheses.

SETTING AND PATIENTS

Eleven patients with breast ALCL were identified in the registry. For each case patient with ALCL in the breast, we selected 1 to 5 controls with other lymphomas in the breast, matched on age and year of diagnosis. For all cases and controls (n = 35), pathological and clinical information was obtained with special emphasis on the presence of a breast prosthesis.

MAIN OUTCOME MEASURE

Association between breast implants and ALCL of the breast.

RESULTS

The 11 patients with ALCL of the breast were diagnosed between 1994 and 2006 at a median age of 40 years (range, 24-68 years). In 5 of these patients, bilateral silicone breast prostheses had been placed 1 to 23 years before diagnosis. All received prostheses for cosmetic reasons. Lymphoma classes of 35 eligible control patients were 12 diffuse large B-cell lymphomas, including 1 T-cell rich B-cell lymphoma; 5 Burkitt lymphomas; 10 mucosa-associated lymphoid tissue-type lymphoma; 3 follicular lymphomas; 3 peripheral T-cell lymphomas; and 2 indolent B-cell lymphomas, unclassified. One of 35 control patients had a breast implant placed before diagnosis of lymphoma. The odds ratio for ALCL associated with breast prostheses was 18.2 (95% confidence interval, 2.1-156.8).

CONCLUSIONS

These preliminary findings suggest an association between silicone breast prostheses and ALCL, although the absolute risk is exceedingly low due to the rare occurrence of ALCL of the breast (11 cases in The Netherlands in 17 years). These findings require confirmation in other studies.

[Granulomatous mastitis: a rare cause of breast swelling]

Three women, aged 37, 39 and 29 years, presented with unilateral painful swelling of the breast. Ultrasound revealed inflammation with abscess formation. Histological biopsies contained granulomatous tissue without necrosis. Corynebacterium species were cultured in the first two patients. All 3 patients were diagnosed with granulomatous mastitis and were successfully treated with doxycycline. Granulomatous mastitis is a rare disorder that may mimic breast carcinoma. It occurs most frequently in fertile women. Diagnosis is based on histological biopsy which shows granulomas without necrosis, while other causes of granulomatous inflammation, especially tuberculosis, have been excluded. The aetiology is not fully understood. It is hypothesised that the granulomatous mastitis is caused by a type IV allergic reaction. Recently an association with Corynebacterium species was suggested. Best practice treatment methods are unclear. Most patients are treated with surgical intervention and steroids, but the rate of recurrence is high (50%). Treatment with doxycycline must be considered in patients with cultured Corynebacterium species.

Monoclonal antibodies against the human mannose receptor as a specific marker in flow cytometry and immunohistochemistry for macrophages

Recently we developed mouse monoclonal antibodies (mAb) against the isolated human 175-kDa mannose receptor. In the present study we tested whether these mAb are suitable for the detection of the mannose receptor on cultured macrophages using flow cytometry and on cells in human tissues using immunohistochemistry. Human monocytes did not react with the mAb in flow cytometry. Mannose receptor expression became detectable on monocytes cultured for 3 days (macrophages), and was maximal from 4 days onward. The mannose receptor was up-regulated on dexamethasone-treated (immunosuppressed) macrophages, and down-regulated on lipopolysaccharide-treated (activated) macrophages. Immunohistochemically the staining pattern of our mAb was compared with the marker of monocytes/macrophages KP1. In a bone marrow smear, only macrophages were stained with our mAb, whereas all myeloid cells were stained with KP1. In the thymus and lymph node, mannose receptor-positive branched cells (macrophages and dendritic cells) were detected in connective tissue, thymus cortex (not medulla), and in the T cell area (not the B cell area) of lymph nodes, whereas KP1 stained branched cells in all areas. It was concluded that the mAb are useful tools in flow cytometry and immunohistochemistry for the specific detection of cells expressing mannose receptor.

A novel bone marrow frozen section assay for studying hematopoietic interactions in situ: the role of stromal bone marrow macrophages in erythroblast binding

Bone marrow macrophages are found in intimate contact with erythroblasts. Exact mechanisms and functions of this interaction are unclear. New insights into erythroblast binding were obtained using a newly developed bone marrow frozen section assay. This modified Woodruff and Stamper assay has some important advantages compared to other adhesion assays. Erythroblasts specifically adhered to bone marrow macrophages forming clusters, as appear in vivo. Selective depletion of bone marrow macrophages by intravenous injection of dichloromethyl-enediphosphonate resulted in a release of immature erythroid cells to the peripheral blood. Furthermore no erythroblasts adhered to bone marrow sections without macrophages. Evaluating the binding of erythroblasts to bone marrow macrophages we found that this binding is temperature and cation dependent. The receptor for erythroblasts present on macrophages recognizes a sialyated protein as ligand on erythroblasts, since neuraminidase treatment of erythroblasts resulted in a decrease in binding. A possible candidate for the erythroblast receptor on macrophages is the ED2 antigen. ED2 is a differentiation antigen present on resident macrophages that has some biochemical features characteristic of an adhesion molecule. Erythroblast binding to bone marrow was inhibited using a monoclonal antibody directed against ED2.

Characterization and expression of the antigen present on resident rat macrophages recognized by monoclonal antibody ED2

Because of the absence of a specific marker for labeling resident macrophages in the rat, there is almost no information available regarding the properties of individual resident macrophages in different organs. The recently described and in our laboratory developed mAb ED2, has been shown to exclusively recognize resident macrophages. The present study examines expression, function and structure of the ED2 antigen to obtain more information about the marker and therefore, more information about resident macrophages. In earlier studies, the expression of ED2 could not be induced by a range of macrophage stimulating factors under non-adherent culture conditions. We show a highly inducible expression of the ED2 antigen under adhering, non proliferating conditions as well as in long-term bone marrow cultures. ED2 appears to recognize a surface protein on resident macrophages consisting of three protein chains of 175, 160, and 95 kDa.