About

Borislav A. Alexiev, MD, is the Vice Chair and Director of Anatomic Pathology at the Department of Pathology, Northwestern University Feinberg School of Medicine. He holds the title of Professor of Pathology. His role involves overseeing anatomic pathology operations and contributing to the academic and clinical missions of the department. Specific details about his research focus, background, or key contributions are not provided in the page text.

Research topics

• Medicine
• Dermatology
• Law
• Surgery
• Pathology
• Immunology

Selected publications

• Not all errors are created equal: assessment of amended diagnoses at a major academic center

  American Journal of Clinical Pathology · 2026-01-09

  article

  OBJECTIVE: We sought to characterize amendment rates, patterns, and turnaround times in surgical pathology and to identify subspecialty and error-specific opportunities for quality improvement. METHODS: All amended surgical pathology and fine-needle aspiration reports from quarter 3 of 2021 to quarter 2 2025 were retrieved through our in-house Epic Beaker system. Amendments were allocated to 1 of 7 predefined error categories and analyzed by year and subspecialty. Amendment rates, odds ratios, and 95% CIs were calculated, and time-to-amend metrics were compared using nonparametric tests with false-discovery-rate correction. RESULTS: Over 5 years, 0.33% of finalized surgical pathology reports were amended (95% CI, 0.31-0.35), within national College of American Pathologists Q-Probes and Q-Tracks program benchmarks, and stable over time (P = .64). Typographical errors predominated (20%-30%), followed by minor diagnostic changes and additional diagnostic information (12%-20%). Major diagnostic amendments declined from 30% (95% CI, 21.5%-40.6%) in 2021 to 15% (95% CI, 9.9%-22.8%) in 2025. Breast pathology showed enrichment of laterality errors (16.1%; odds ratio, 4.68 [95% CI, 2.65-8.27]; q = 8.26 ×10-6), gastrointestinal cases were enriched for anatomic-site errors (15.4%; odds ratio, 2.80 [95% CI, 1.71-4.56]; q = 9.28 ×10-4). Median amendment turnaround time was 1 to 3 days overall, with the longest for laterality and major diagnostic changes. Among major diagnostic changes, benign to malignant reclassification and vice versa made up roughly half. Cytology fine-needle aspiration amendments were rare (0.19%), with similar times to amend across all error categories. CONCLUSIONS: Amendments in surgical pathology are uncommon, timely, and stable. Subspecialty-specific amendment patterns highlight discrete areas for targeted quality improvement and focused secondary review.

  PublisherDOI

• 1621 Hepatoid Adenocarcinoma of Lung Retains Selective Hepatic Oncogenic Programs Within a Lung-Like Transcriptome

  Laboratory Investigation · 2026-03-01

  articleOpen access
  PublisherOA PDFDOI

• Revisiting the Immune Frontier in Soft Tissue Sarcomas

  Current Oncology Reports · 2026-03-17

  articleOpen access

  PURPOSE OF REVIEW: Soft tissue sarcomas (STS) comprise a heterogeneous group of mesenchymal malignancies with limited treatment options and poor outcomes in the advanced setting. Although immune checkpoint inhibitors have transformed the management of many solid tumors, their efficacy in STS has been modest and strongly histology dependent. This review aims to synthesize recent advances in immuno-oncology as applied to STS and to highlight emerging strategies that may overcome resistance and improve patient outcomes. RECENT FINDINGS: Thus far, clinically meaningful activity of immune checkpoint inhibitors has been identified select STS subtypes, including undifferentiated pleomorphic sarcoma, angiosarcoma, and alveolar soft part sarcoma. Combination approaches incorporating immune checkpoint inhibitors with chemotherapy, radiation, tyrosine kinase inhibitors, or novel immune modulators have shown enhanced antitumor activity in early-phase and randomized trials. In parallel, engineered T-cell therapies targeting cancer-testis antigens have emerged as a standard-of-care option in synovial sarcoma and are being expanded to other histologies. Finally, advances in tumor microenvironment characterization, including the role of tertiary lymphoid structures and myeloid modulation, are refining patient selection and informing rational trial design. Immunotherapy continues to reshape the therapeutic landscape of soft tissue sarcoma. While immune checkpoint blockade alone benefits only a subset of patients, rational combination strategies and cellular therapies offer promising avenues to broaden clinical efficacy. Continued integration of biomarker-driven approaches, translational correlative studies, and histology-specific trial designs will be essential to fully realize the potential of immunotherapy in STS.

  PublisherOA PDFDOI

• Intratumoral TLR4 agonist therapy elicits antigen-specific T cell clonal expansion in metastatic leiomyosarcoma: a case series

  Frontiers in Oncology · 2026-05-20

  articleOpen access

  Metastatic soft tissue sarcomas (STSs) are a heterogeneous group of rare mesenchymal tumors whose treatment options are limited. Our group has been interested in utilizing the synthetic toll-like receptor 4 (TLR4) agonist, glycopyranosyl lipid A in stable-emulsion formulation (GLA-SE), in patients with advanced STSs. Here, we report a case series of three patients with metastatic leiomyosarcoma who had superficial lesions amenable to intratumoral (IT) injection. We explored the safety, tolerability, and immunologic effects of IT GLA-SE given at 20 μg weekly for 12 weeks, both alone and in combination with radiotherapy. In this small case series, treatment was well tolerated, with no serious adverse events observed. Clinically, although no patient had significant tumor shrinkage, two had notable stability in their target lesions despite systemic disease progression. Immunologically, IT GLA-SE induced a clonal expansion of T cells intratumorally in one patient and in peripheral blood in another, suggesting an antitumor effect both at the site of injection and systemically. Moreover, GLA-SE elicited clonal expansion of systemic T cells targeting a well-known immunogenic cancer antigen, NY-ESO-1. The augmented expression of T cells targeting NY-ESO-1 in the systemic circulation of our patient following IT-GLA-SE warrants further investigation, given the promising role of NY-ESO-1 in current and future T-cell based immunotherapies. Together, these findings demonstrate the potential of IT GLA-SE to elicit antigen-specific T cell clonal expansion as a component of immunotherapeutic strategies to combat metastatic STSs. Expanded studies are needed to explore the clinical and immunologic effects of IT GLA-SE, particularly in combination with other immunotherapies.

  PublisherOA PDFDOI

• Hepatoid adenocarcinoma of the lung: clinicopathologic and molecular analysis of 17 cases

  Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin · 2026-05-07

  articleOpen accessSenior author

  Hepatoid adenocarcinoma of the lung (HAL) is a rare subtype of non-small cell lung carcinoma characterized by morphologic and immunophenotypic overlap with hepatocellular carcinoma (HCC), creating diagnostic challenges for practicing pathologists. Because of its rarity, only limited information exists regarding its molecular profile and biologic behavior. We retrospectively analyzed 17 HAL cases diagnosed at Northwestern Memorial Hospital and describe their clinical presentation, morphologic features, immunohistochemical and molecular profiles, and clinical outcomes. Histologically, HAL is composed of polygonal to columnar epithelioid cells with abundant lightly eosinophilic, finely granular cytoplasm and predominantly solid and/or complex glandular growth patterns. Foci of mucinous differentiation may be present. Cytologic atypia, brisk mitotic activity, and tumor necrosis are common findings. Immunohistochemically, HAL is characterized by strong and diffuse HepPar1 expression, positivity for adenocarcinoma markers such as MOC31, and cytoplasmic immunoreactivity for TTF-1. Across the 17 cases, STK11 alterations were most frequent (52.9%), followed by TP53 (41.2%) and KRAS (35.3%). Concurrent KRAS + STK11 alterations were identified in 23.5% of cases, compared with The Cancer Genome Atlas (TCGA) cohorts of other lung adenocarcinomas (11/566, 2.0%) and HCC (0/372, 0%). HAL demonstrates highly aggressive behavior, with metastatic presentation even in low-stage tumors (T1: 33.3%; T2: 71.4%), frequent hematogenous spread, and death of disease in 41.2% of patients at a median follow-up of 5 months. In summary, HAL is a distinct subtype with characteristic morphologic and immunohistochemical features. Given its aggressive clinical course, accurate diagnosis is essential for patient management.

  PublisherOA PDFDOI

• HPV-Associated Sarcomatoid (Spindle Cell) Carcinoma of the Base of the Tongue with HRAS and TERT Promoter Mutations

  Head and Neck Pathology · 2026-05-14

  articleOpen accessSenior author
  PublisherOA PDFDOI

• 68. MYCN or MDM2 amplifications in PAX3::FOXO1 fusion positive adolescent and adult alveolar rhabdomyosarcoma

  Cancer Genetics · 2025-12-01

  article
  PublisherDOI

• Trends and outcomes for patients receiving neoadjuvant therapy for stage I to III gastric gastrointestinal stromal tumors

  Journal of Gastrointestinal Surgery · 2025-06-16

  article
  PublisherDOI

• Phase <scp>II</scp> Study of Nivolumab and Ipilimumab for Treatment of Metastatic/Recurrent Adenoid Cystic Carcinoma (<scp>ACC</scp>) of all Anatomic Sites of Origin and Other Malignant Salivary Gland Tumors

  Cancer Medicine · 2025-04-01 · 4 citations

  articleOpen access

  OBJECTIVE: Dual checkpoint inhibitor therapy with nivolumab and ipilimumab has been FDA approved for a number of cancer sites. However, its role in the treatment of ACC and non-ACC salivary gland carcinomas (non-ACC SGC) is not well established. METHODS AND ANALYSIS: We performed Simon's two-stage prospective single-institution Phase II clinical trial of nivolumab with ipilimumab. Two cohorts were analyzed: patients with metastatic/recurrent ACC and patients with non-ACC SGC. The primary endpoint was median progression-free survival (PFS); secondary endpoints were overall response rate (ORR), overall survival (OS), and toxicity. RESULTS: Patient enrollment was prematurely terminated due to funding constraints. In total, 19 patients with ACC and 5 patients with non-ACC SGC were enrolled. The patients with ACC had a median OS of 30.0 months (95% CI 15.3-NR months), a median PFS of 8.3 months (95% CI 5.5-30.0 months), and a disease control rate (DCR) of 53% (10/19). The ORR in the ACC group was 5% (CR 0%, n = 0; confirmed PR 5%, n = 1), with one patient having continued stable disease at the time of trial conclusion. The patients with non-ACC SGC had a median OS of 10.4 months (95% CI 6.21-NR months), a median PFS of 6.21 months (95% CI 2.83-NR months), and a DCR of 40% (2/5). The ORR in this cohort was 0%. CONCLUSION: In patients with recurrent or metastatic ACC and non-ACC SGC, the combination of nivolumab with ipilimumab resulted in moderate disease control. Further studies are warranted to validate our findings. TRIAL NUMBER: NCT03146650.

  PublisherOA PDFDOI

• Paradoxical Response to Neoadjuvant Therapy in Undifferentiated Pleomorphic Sarcoma: Increased Tumor Size on MRI Associated with Favorable Pathology

  Cancers · 2025-02-27 · 3 citations

  articleOpen access

  Background/Objectives: To correlate size changes in undifferentiated pleomorphic sarcoma (UPS) on magnetic resonance imaging (MRI) after neoadjuvant chemoradiation therapy (nCRT) with pathological response, risk of local recurrence, and therapeutic regimens. Methods: This retrospective study analyzed clinical, pathological, and imaging data from 39 biopsy-proven UPS subjects. Four readers measured the tumor dimensions before and after nCRT, including two perpendicular axial diameters and the longest coronal/sagittal diameter. Three cross-sectional areas and bounding volume were also calculated. Responders (pR) were defined as having ≤10% viable cells and non-responders (pNR) as having more. Inter-reader agreement was evaluated using Kendall’s concordance coefficient. Changes in tumor size were compared between pR and pNR using one-way ANOVA and Tukey’s HSD test for multiple comparisons of means. Results: pR showed a greater increase in size across all measurements compared to pNR. For the longest axial diameter, the mean increase was 30% ± 35% for pR and 14% ± 31% for pNR, with a mean difference (pR-pNR) of 16% (95% CI: 6–27%, p = 0.003). In tumors treated with radiotherapy alone, pR exhibited larger size increases in all dimensions compared to pNR. In contrast, in the chemoradiation group, pR showed a slight increase, while pNR generally shrank, although these differences did not reach statistical significance. Notably, pNR with local recurrence exhibited a reduction in all tumor dimensions compared to pNR without local recurrence. Conclusions: This exploratory study suggests that tumor size changes may predict pathological response and local recurrence after nCRT in UPS; however, the small sample size limits the generalizability of these findings.

  PublisherOA PDFDOI

Frequent coauthors

• Aiman Ali

  University of Toronto

  50 shared

• Esmeralda Celia Marginean

  50 shared

• Augusto Pappalardo

  IRCCS San Camillo Hospital

  50 shared

• Claudio Tondo

  University of Milan

  50 shared

• Paola F. Silenzi

  Sapienza University of Rome

  50 shared

• Intezar Ahmed

  National Institute for Health Research

  50 shared

• G D'

  Sapienza University of Rome

  50 shared

• SM Rashed Ul Islam

  Bangabandhu Sheikh Mujib Medical University

  50 shared