Sclerosing well-differentiated liposarcoma: two diagnostically challenging mimicker cases and a literature review.

Liposarcoma is a malignant soft tissue tumor with several subtypes, the most common of which is well-differentiated liposarcoma (WDL) or atypical lipomatous tumor (ALT). WDL/ALTs are further divided into three histological subtypes, including lipoma-like, sclerosing, and inflammatory. While the majority of these tumors are predominantly fatty, the sclerosing variant demonstrates diverse histologic and radiographic characteristics, including variable amounts of fibrosis and fat. Because of this histological variability and relative rarity, the sclerosing WDL/ALT can present diagnostic dilemmas. We present two cases of sclerosing WDL/ALT, both of which demonstrated high degrees of fibrosis and a paucity of fat, mimicking desmoid fibromatosis and other fibrotic soft tissue tumors. Thus, it is important for radiologists to be aware of the subtypes of liposarcoma and their unique characteristics, and to consider sclerosing WDL/ALT in cases of fibrotic soft tissue tumors.

Whole-Genome Sequencing Analysis of Male Breast Cancer Unveils Novel Structural Events and Potential Therapeutic Targets.

The molecular characterization of male breast cancer (MaBC) has received limited attention in research, mostly because of its low incidence rate, accounting for only 0.5% to 1% of all reported cases of breast cancer each year. Managing MaBC presents significant challenges, with most treatment protocols being adapted from those developed for female breast cancer. Utilizing whole-genome sequencing (WGS) and state-of-the-art analyses, the genomic features of 10 MaBC cases (n = 10) were delineated and correlated with clinical and histopathologic characteristics. Using fluorescence in situ hybridization, an additional cohort of 18 patients was interrogated to supplement WGS findings. The genomic landscape of MaBC uncovered significant genetic alterations that could influence diagnosis and treatment. We found common somatic mutations in key driver genes, such as FAT1, GATA3, SMARCA4, and ARID2. Our study also mapped out structural variants that impact cancer-associated genes, such as ARID1A, ESR1, GATA3, NTRK1, and NF1. Using a WGS-based classifier, homologous recombination deficiency (HRD) was identified in 2 cases, both presenting with deleterious variants in BRCA2. Noteworthy was the observation of FGFR1 amplification in 21% of cases. Altogether, we identified at least 1 potential therapeutic target in 8 of the 10 cases, including high tumor mutational burden, FGFR1 amplification, and HRD. Our study is the first WGS characterization of MaBC, which uncovered potentially relevant variants, including structural events in cancer genes, HRD signatures, and germline pathogenic mutations. Our results demonstrate unique genetic markers and potential treatment targets in MaBC, thereby underlining the necessity of tailoring treatment strategies for this understudied patient population. These WGS-based findings add to the growing knowledge of MaBC genomics and highlight the need to expand research on this type of cancer.

Patient-derived tumor organoids with p53 mutations, and not wild-type p53, are sensitive to synergistic combination PARP inhibitor treatment.

Poly (ADP-ribose) polymerase inhibitors (PARPi) are used for patients with BRCA1/2 mutations, but patients with other mutations may benefit from PARPi treatment. Another mutation that is present in more cancers than BRCA1/2 is mutation to the TP53 gene. In 2D breast cancer cell lines, mutant p53 (mtp53) proteins tightly associate with replicating DNA and Poly (ADP-ribose) polymerase (PARP) protein. Combination drug treatment with the alkylating agent temozolomide and the PARPi talazoparib kills mtp53 expressing 2D grown breast cancer cell lines. We evaluated the sensitivity to the combination of temozolomide plus PARPi talazoparib treatment to breast and lung cancer patient-derived tumor organoids (PDTOs). The combination of the two drugs was synergistic for a cytotoxic response in PDTOs with mtp53 but not for PDTOs with wtp53. The combination of talazoparib and temozolomide induced more DNA double-strand breaks in mtp53 expressing organoids than in wild-type p53 expressing organoids as shown by increased γ-H2AX protein expression. Moreover, breast cancer tissue microarrays (TMAs) showed a positive correlation between stable p53 and high PARP1 expression in sub-groups of breast cancers, which may indicate sub-classes of breast cancers sensitive to PARPi therapy. These results suggest that mtp53 could be a biomarker to predict response to the combination of PARPi talazoparib-temozolomide treatment.

Patient-derived tumor organoids with p53 mutations, and not wild-type p53, are sensitive to synergistic combination PARP inhibitor treatment.

Poly (ADP-ribose) polymerase inhibitors (PARPi) are used for patients with BRCA1/2 mutations, but patients with other mutations may benefit from PARPi treatment. Another mutation that is present in more cancers than BRCA1/2 is mutation to the TP53 gene. In 2D breast cancer cell lines, mutant p53 (mtp53) proteins tightly associate with replicating DNA and Poly (ADP-ribose) polymerase (PARP) protein. Combination drug treatment with the alkylating agent temozolomide and the PARPi talazoparib kills mtp53 expressing 2D grown breast cancer cell lines. We evaluated the sensitivity to the combination of temozolomide plus PARPi talazoparib treatment to breast and lung cancer patient-derived tumor organoids (PDTOs). The combination of the two drugs was synergistic for a cytotoxic response in PDTOs with mtp53 but not for PDTOs with wtp53. The combination of talazoparib and temozolomide induced more DNA double-strand breaks in mtp53 expressing organoids than in wild-type p53 expressing organoids as shown by increased γ-H2AX protein expression. Moreover, breast cancer tissue microarrays (TMAs) showed a positive correlation between stable p53 and high PARP1 expression in sub-groups of breast cancers, which may indicate sub-classes of breast cancers sensitive to PARPi therapy. These results suggest that mtp53 could be a biomarker to predict response to the combination of PARPi talazoparib-temozolomide treatment.

Dedifferentiated Chondrosarcoma: Diagnostic Controversies and Emerging Therapeutic Targets.

PURPOSE OF REVIEW: The pathogenesis of dedifferentiated chondrosarcoma is controversial, and no genetic abnormality has consistently been identified in the disease. Focusing on the diagnostic challenges encountered in dedifferentiated chondrosarcoma, the following review aims at summarizing the tumor's active neoplastic pathways while highlighting therapeutic modalities that could potentially be explored to enhance patient survivorship. RECENT FINDINGS: Owing to the challenging examination of small needle biopsy sampling as well as the disease's overlapping morphological and immunohistochemical features with other bone and soft-tissue sarcomas, the diagnosis of dedifferentiated chondrosarcoma can be problematic. While combined doxorubicin- and cisplatin-based regimens remain the first-line systemic chemotherapy in the disease, ~50% of tumors carry EXT1/2 or IDH1/2 mutations, advancing EXT or IDH inhibitors as potential alternative therapies, respectively. Despite systemic chemotherapy, dedifferentiated chondrosarcoma remains an aggressive tumor with dismal prognosis and limited survival. A multidisciplinary collaboration across multiple cancer centers is warranted to yield an accurate diagnosis, understand the disease's underlying pathogenesis, develop adequate treatment, and improve patient survivorship.

Development of multiple AI pipelines that predict neoadjuvant chemotherapy response of breast cancer using H&E-stained tissues.

In recent years, the treatment of breast cancer has advanced dramatically and neoadjuvant chemotherapy (NAC) has become a common treatment method, especially for locally advanced breast cancer. However, other than the subtype of breast cancer, no clear factor indicating sensitivity to NAC has been identified. In this study, we attempted to use artificial intelligence (AI) to predict the effect of preoperative chemotherapy from hematoxylin and eosin images of pathological tissue obtained from needle biopsies prior to chemotherapy. Application of AI to pathological images typically uses a single machine-learning model such as support vector machines (SVMs) or deep convolutional neural networks (CNNs). However, cancer tissues are extremely diverse and learning with a realistic number of cases limits the prediction accuracy of a single model. In this study, we propose a novel pipeline system that uses three independent models each focusing on different characteristics of cancer atypia. Our system uses a CNN model to learn structural atypia from image patches and SVM and random forest models to learn nuclear atypia from fine-grained nuclear features extracted by image analysis methods. It was able to predict the NAC response with 95.15% accuracy on a test set of 103 unseen cases. We believe that this AI pipeline system will contribute to the adoption of personalized medicine in NAC therapy for breast cancer.

African Ancestry-Associated Gene Expression Profiles in Triple-Negative Breast Cancer Underlie Altered Tumor Biology and Clinical Outcome in Women of African Descent.

Women of sub-Saharan African descent have disproportionately higher incidence of triple-negative breast cancer (TNBC) and TNBC-specific mortality across all populations. Population studies show racial differences in TNBC biology, including higher prevalence of basal-like and quadruple-negative subtypes in African Americans (AA). However, previous investigations relied on self-reported race (SRR) of primarily U.S. populations. Due to heterogeneous genetic admixture and biological consequences of social determinants, the true association of African ancestry with TNBC biology is unclear. To address this, we conducted RNA sequencing on an international cohort of AAs, as well as West and East Africans with TNBC. Using comprehensive genetic ancestry estimation in this African-enriched cohort, we found expression of 613 genes associated with African ancestry and 2,000+ associated with regional African ancestry. A subset of African-associated genes also showed differences in normal breast tissue. Pathway enrichment and deconvolution of tumor cellular composition revealed that tumor-associated immunologic profiles are distinct in patients of African descent. SIGNIFICANCE: Our comprehensive ancestry quantification process revealed that ancestry-associated gene expression profiles in TNBC include population-level distinctions in immunologic landscapes. These differences may explain some differences in race-group clinical outcomes. This study shows the first definitive link between African ancestry and the TNBC immunologic landscape, from an African-enriched international multiethnic cohort. See related commentary by Hamilton et al., p. 2496. This article is highlighted in the In This Issue feature, p. 2483.

ORAI3 is dispensable for store-operated Ca2+ entry and immune responses by lymphocytes and macrophages.

Ca2+ signals regulate the function of many immune cells and promote immune responses to infection, cancer, and autoantigens. Ca2+ influx in immune cells is mediated by store-operated Ca2+ entry (SOCE) that results from the opening of Ca2+ release-activated Ca2+ (CRAC) channels. The CRAC channel is formed by three plasma membrane proteins, ORAI1, ORAI2, and ORAI3. Of these, ORAI1 is the best studied and plays important roles in immune function. By contrast, the physiological role of ORAI3 in immune cells remains elusive. We show here that ORAI3 is expressed in many immune cells including macrophages, B cells, and T cells. To investigate ORAI3 function in immune cells, we generated Orai3-/- mice. The development of lymphoid and myeloid cells in the thymus and bone marrow was normal in Orai3-/- mice, as was the composition of immune cells in secondary lymphoid organs. Deletion of Orai3 did not affect SOCE in B cells and T cells but moderately enhanced SOCE in macrophages. Orai3-deficient macrophages, B cells, and T cells had normal effector functions in vitro. Immune responses in vivo, including humoral immunity (T cell dependent or independent) and antitumor immunity, were normal in Orai3-/- mice. Moreover, Orai3-/- mice showed no differences in susceptibility to septic shock, experimental autoimmune encephalomyelitis, or collagen-induced arthritis. We conclude that despite its expression in myeloid and lymphoid cells, ORAI3 appears to be dispensable or redundant for physiological and pathological immune responses mediated by these cells.

Papillary Breast Tumors: Continuing Controversies and Commentary on WHO's 2019 Criteria and Classification.

The category of papillary breast tumors includes a limited number of entities. Nonetheless, this relatively uncommon group of tumors seems to instigate a disproportionate degree of diagnostic disquiet. As a group, papillary breast tumors suffer from a relatively high rate of discordant interpretation. The latter is due to the inherent complexity of the lesions compounded by conflicting criteria as well as simmering controversies. For instance, "encapsulated" papillary carcinoma remains contentious with regards to whether these are noninvasive or not, and the assessment of the extent of the invasive versus noninvasive components in many solid papillary carcinomas can be problematic. The latest classification system of breast tumors enunciated by the World Health Organization (WHO), that is, Breast Tumors, which appeared in 2019, mainly sought to incorporate advances in basic and clinical sciences into diagnostic criteria for the entire spectrum of breast neoplasms-including papillary ones. The latter category of tumors is discussed at some length in Breast Tumors; however, it still appears to suffer from some lack of clarity in its subclassification. It is our intent in this communication to provide an overview of the controversies around papillary breast tumors, and offer comments on its coverage in Breast Tumors-so that any tangible or perceived ambiguities therein could be addressed in its next edition.

Monophasic Synovial Sarcoma in the Elbow Misclassified but Successfully Treated as Ewing's Sarcoma with Chemotherapy.

To the best of the authors' knowledge, this is the first published case of monophasic synovial sarcoma (SS) initially diagnosed as Ewing's sarcoma (ES), yet successfully treated with chemotherapy in a 24-year-old patient. The initial diagnosis showed a monotonous round cell tumor and positivity for CD99, characteristic of ES; however, the cytology was negative for the classic EWSR1 rearrangement of ES. The patient was treated with the standard chemotherapy protocol of ES - COG AEWS1031 Regimen A with vincristine, doxorubicin, cyclophosphamide, and mesna - as well as with wide resection. Post-resection tissue submission showed additional morphologic features which led to a re-evaluation of the classification of the tumor as well as additional molecular studies; these revealed positivity for translocations of SS18 (18q11.1) in 100% of the nuclei, which is most characteristic of SS, thus, reclassifying the neoplasm as a SS tumor. This case underscores the importance of considering several pathologic entities in the differential diagnosis of small, round blue cell tumors, including ES, SS, and lymphoma. It also demonstrates the importance of using chromosomal identification for a more definitive diagnosis, rather than relying on histological features and markers which are found in more than one tumor classification. There is conflicting evidence of the impact of chemotherapy on survival in SS, as it is primarily treated with radiation therapy. Since SS is rare, prospective studies on the effect of chemotherapy on survival are limited in number. However, our case study demonstrates that chemotherapy is another modality that can be used in the treatment of SS neoplasms.

Tumor-Induced Osteomalacia Localized and Excised After Pregnancy.

OBJECTIVE: Tumor-induced osteomalacia (TIO) is a rare osteomalacia characterized by paraneoplastic secretion of fibroblast growth factor 23. Concomitant occurrence of TIO during pregnancy is rarer still. Our objective was to report a young patient with debilitating fractures diagnosed with TIO who became pregnant and subsequently had her tumor localized by gallium-68 (Ga-68) DOTATATE positron emission tomography/magnetic resonance imaging (PET/MRI). CASE REPORT: A 28 year-old woman with a 2-year history of stress fractures was found to have the following: (1) alkaline phosphatase level, 220 (reference range, 30-95) U/L; (2) phosphorus level, 2.1 (2.5-5.0) mg/dL; (3) 1,25-dihydroxyvitamin D3 level, <8 (18-72) pg/mL; (4) 24-hour urine phosphorus level, 0.5 (0.3-1.3) g; and (5) fibroblast growth factor 23 levels, 1241 (reference range, <180) RU/mL. The patient became pregnant, and at term, a cesarean delivery was performed. Ga-68 DOTATATE PET/MRI showed a 9-mm intracortical mass in the right fibular head and right femoral and bilateral calcaneal stress fractures. The fibular lesion was resected; pathology showed a 1.5-cm lesion with positive fibroblast growth factor receptor 1 staining. DISCUSSION: This patient with TIO had an uneventful pregnancy and delivery. TIO is typically caused by benign mesenchymal tumors. Ga-68 DOTATATE PET/computed tomography has been used for localizing tumors causing TIO, yet MRI has superior contrast resolution over computed tomography. Therefore, it is not surprising that Ga-68 PET/MRI successfully localized this patient's tumor to the intracortical space of the fibular head and distinguished it from insufficiency fractures. CONCLUSION: To our knowledge, this is the first report of phosphate treatment in a pregnant patient with TIO and the first report of a tumor-inducing TIO being localized by Ga-68 DOTATATE PET/MRI.

Metastasis of Cutaneous B-Cell Lymphoma Affecting the Metatarsal Head: A Case Report.

There are few reported cases of non-Hodgkin's lymphoma metastasis to bone in the lower extremities. The authors present a case of cutaneous B-cell lymphoma thought to be in remission, with metastasis to the first metatarsal head with involvement in the synovial tissue of the first metatarsophalangeal joint. Following excision of the lesion, no further treatment was determined to be necessary. The patient was to be observed for local recurrence.

Investigation of triple-negative breast cancer risk alleles in an International African-enriched cohort.

Large-scale efforts to identify breast cancer (BC) risk alleles have historically taken place among women of European ancestry. Recently, there are new efforts to verify if these alleles increase risk in African American (AA) women as well. We investigated the effect of previously reported AA breast cancer and triple-negative breast cancer (TNBC) risk alleles in our African-enriched International Center for the Study of Breast Cancer Subtypes (ICSBCS) cohort. Using case-control, case-series and race-nested approaches, we report that the Duffy-null allele (rs2814778) is associated with TNBC risk (OR = 3.814, p = 0.001), specifically among AA individuals, after adjusting for self-indicated race and west African ancestry (OR = 3.368, p = 0.007). We have also validated the protective effect of the minor allele of the ANKLE1 missense variant rs2363956 among AA for TNBC (OR = 0.420, p = 0.005). Our results suggest that an ancestry-specific Duffy-null allele and differential prevalence of a polymorphic gene variant of ANKLE1 may play a role in TNBC breast cancer outcomes. These findings present opportunities for therapeutic potential and future studies to address race-specific differences in TNBC risk and disease outcome.

Intraductal Papilloma of the Breast: Prevalence of Malignancy and Natural History Under Active Surveillance.

BACKGROUND: The optimal management of intraductal papillomas (IPs) without atypia diagnosed on needle core biopsy (NCB) is unclear. This study analyzed the malignancy risk of immediately excised IPs and characterized the behavior of IPs under active surveillance (AS). METHODS: We retrospectively reviewed the pathology and imaging records of patients diagnosed with IPs without atypia on NCB during a 10-year period (1999-2019). The malignancy upgrade rate was assessed in patients who had an immediate surgical excision, and the rates of both radiographic progression and development of malignancy were assessed in a cohort of patients undergoing AS. RESULTS: The inclusion criteria were met in 152 patients with 175 IPs with a mean age of 51 ± 13 years. The average size of the IPs on initial imaging was 8 ± 4 mm. Most of the lesions (57%, n = 99) were immediately excised, whereas 76 (43%) underwent AS with interval imaging with a median follow-up period of 15 months (range, 5-111 months). Among the immediately excised IPs, surgical pathology revealed benign findings in 97% (n = 96) and ductal carcinoma in situ in 3% (n = 3). In the AS cohort, 72% (n = 55) of the IPs remained stable, and 25% (n = 19) resolved or decreased in size. At 2 years, 4% had increased in size on imaging and were subsequently excised, with ductal carcinoma in situ (DCIS, n = 1) and benign pathology (n = 1) noted on final pathology. CONCLUSIONS: In a large series of breast IPs without atypia, no invasive carcinoma was observed after immediate excision, and 96% of the lesions had not progressed on AS. This suggests that patients with IP shown on NCB can safely undergo AS, with surgery reserved for radiographic lesion progression.