When a dermatopathologist encounters the ultra-rare: A case series of superficial soft tissue/cutaneous myxopapillary ependymomas.

Myxopapillary ependymoma (MPE) is an uncommon variant of ependymoma, almost exclusively seen in conus medullaris or filum terminale. MPE can be diagnostically challenging, especially when arising extra-axially. Here we report 5 cases of superficial soft tissue/cutaneous MPE, identified across three tertiary institutions. All patients were female and three of them (3/5, 60%) were children (median age 11 years, range 6-58 years). The tumors presented as slow-growing masses of the sacrococcygeal subcutaneous soft tissues, occasionally identified after minor trauma and clinically favored to be pilonidal sinuses. Imaging showed no neuraxis connection. Macroscopically, tumors were well-circumscribed, lobulated, and solid and microscopically they exhibited typical histopathology of MPE, at least focally. Two of the tumors (2/5, 40%) showed predominantly solid or trabecular architecture with greater cellular pleomorphism, scattered giant cells, and increased mitotic activity. All tumors (5/5, 100%) showed strong diffuse immunohistochemical expression of GFAP. One tumor clustered at the category "ependymoma, myxopapillary" by methylome analysis. Two patients (2/5, 40%) had local recurrence at 8 and 30 months after the initial surgery. No patients developed metastases during the follow-up period (median 60 months, range 6-116 months). Since a subset of extra-axial MPEs behaves more aggressively, timely and accurate diagnosis is of paramount importance.

Transcriptomic and immunophenotypic characterization of two cases of adamantinoma-like Ewing sarcoma of the thyroid gland.

INTRODUCTION: Adamantinoma-like Ewing sarcoma (ALES) is a rare aggressive malignancy occasionally diagnosed in the thyroid gland. ALES shows basaloid cytomorphology, expresses keratins, p63, p40, frequently CD99, and harbours the t(11;22) EWSR1::FLI1 translocation. There is debate on whether ALES resembles more sarcoma or carcinoma. METHODS: We performed RNA sequencing from two ALES cases and compared findings with skeletal Ewing's sarcomas and nonneoplastic thyroid tissue. ALES was investigated by in situ hybridization (ISH) for high-risk human papillomavirus (HPV) DNA and immunohistochemistry for the following antigens: keratin 7, keratin 20, keratin 5, keratins (AE1/AE3 and CAM5.2), CD45, CD20, CD5, CD99, chromogranin, synaptophysin, calcitonin, thyroglobulin, PAX8, TTF1, S100, p40, p63, p16, NUT, desmin, ER, FLI1, INI1, and myogenin. RESULTS: An uncommon EWSR1::FLI transcript with retained EWSR1 exon 8 was detected in both ALES cases. Regulators of EWSR1::FLI1 splicing (HNRNPH1, SUPT6H, SF3B1) necessary for production of a functional fusion oncoprotein, as well as 53 genes (including TNNT1, NKX2.2) activated downstream to the EWSR1::FLI1 cascade, were overexpressed. Eighty-six genes were uniquely overexpressed in ALES, most of which were related to squamous differentiation. Immunohistochemically, ALES strongly expressed keratins 5, AE1/AE3 and CAM5.2, p63, p40, p16, and focally CD99. INI1 was retained. The remaining immunostains and HPV DNA ISH were negative. CONCLUSION: Comparative transcriptomic profiling reveals overlapping features of ALES with skeletal Ewing's sarcoma and an epithelial carcinoma, as evidenced by immunohistochemical expression of keratin 5, p63, p40, CD99, the transcriptome profile, and detection of EWSR1::FLI1 fusion transcript by RNA sequencing.

Prognostic impact of stromal and intratumoral CD3, CD8 and FOXP3 in adjuvantly treated breast cancer: do they add information over stromal tumor-infiltrating lymphocyte density?

BACKGROUND: Tumor-infiltrating lymphocytes (TILs) and their subsets contribute to breast cancer prognosis. We investigated the prognostic impact of CD3+, CD8+ and FOXP3+ TILs in patients with early intermediate/high-risk breast cancer treated with adjuvant anthracycline-based chemotherapy within two randomized trials conducted by our Group. METHODS: We examined 1011 patients (median follow-up 130.9 months) and their tumors for total, stromal (s) and intratumoral (i) CD3, CD8 and FOXP3 lymphocyte density (counts/mm2) on tissue-microarray cores by immunohistochemistry. Morphological sTIL density on whole H&E-stained sections was also evaluated. RESULTS: The majority of TILs were CD3+. Total CD3 and CD8, sCD3 and sCD8, iCD3 and iCD8, sFOXP3 and iFOXP3 were strongly correlated (Spearman's rho values > 0.6). High individual lymphocytic subsets and sTIL density were strongly associated with high tumor grade, higher proliferation and HER2-positive and triple-negative tumors (all p values < 0.001). Higher sTIL density (10% increments), high density of almost each individual marker and all-high profiles conferred favorable prognosis. However, when adjusted for sTIL density, stromal and intratumoral lymphocytic subsets lost their prognostic significance, while higher sTIL density conferred up to 15% lower risk for relapse. Independently of sTIL density, higher total CD3+ and CD8+ TILs conferred 35% and 28% lower risk for relapse, respectively. CONCLUSIONS: Stromal and intratumoral CD3+, CD8+ and FOXP3+ TIL density do not seem to add prognostic information over the morphologically assessed sTIL density, which is worth introducing in routine histology reports.

Clinicopathologic predictors of survival in buccal squamous cell carcinoma.

BACKGROUND: Buccal squamous cell carcinoma (SCC) is a locoregionally aggressive malignancy, representing a small subset of oral cancers in North America. We investigated the prognostic value of several clinicopathologic factors in a cohort of patients diagnosed with buccal SCC. METHODS: Between years 1992 and 2017, 52 patients were diagnosed with conventional buccal SCC. Archival surgical pathology material was retrospectively reviewed for reportable findings according to the latest reporting guidelines published by the College of American Pathologists. Clinical data were obtained through chart review. RESULTS: The majority of patients were of older age, current or past smokers, and without specific gender predilection. Most presented at a clinically advanced stage and were treated with surgery alone, or surgery followed by adjuvant radiotherapy. The tumor recurred in about 40% of patients, and almost half of the patients died from the disease by the end of the follow-up period. The worst pattern of invasion (WPOI) was associated with greater depth of invasion (DOI) (P = .031) and perineural invasion (P < .001). In univariate analyses, older age (P = .004), positive nodal status (P = .047), lymphovascular invasion (P = .012), perineural invasion (P = .05), and WPOI-5 (P = .015) were adverse predictors of 5-year overall survival (OS). In multivariate analysis, older age (P = .011), WPOI-5 (P < .001), and perineural invasion (P = .001) remained statistically significant independent prognosticators of worse 5-year OS. CONCLUSIONS: Older age, WPOI-5, and perineural invasion are significant prognosticators of worse OS. WPOI is associated with DOI, a finding which may have important implications for the pathogenesis and biologic behavior of the disease.

Review of treatment modalities and outcomes of patients with basal cell adenocarcinoma.

PURPOSE: This study summarizes the treatment modalities of basal cell adenocarcinoma (BCAC) of the parotid gland and subsequent outcome at a single institution to better define the treatment of this rare tumor. MATERIAL AND METHODS: A retrospective review of patients treated for BCAC of the parotid gland from 1/01/1996 to 08/1/2018 was performed. Patients were identified using our institution's Cancer Registry. RESULTS: A total of thirteen patients (46% female, median age of 56) treated for BCAC of the parotid gland were identified. Eight patients (57%) were staged as T1, four were staged as T2 (29%), and two were stage T4a (14%) due to tumor involvement of the facial nerve. None of the patients had nodal involvement or distant metastases. Three patients (21%) underwent radiation therapy ranging from 60-70Gy for positive margin or facial nerve involvement by tumor. Five patients (36%) underwent a neck dissection (ND) ranging from just a level IIb dissection up to levels IIa, IIb, and III with none of the nodes being positive for disease. The remainder of patients did not undergo a neck dissection. Follow-up was 8.1 ± 6.2 (mean ± SD) years with no local or regional recurrence at time of last follow-up in any patient cohort. CONCLUSIONS: Our review suggests that elective neck dissections are not necessary following resection of T1/T2N0M0 basal cell adenocarcinoma for the prevention of local or regional recurrence. No longer performing neck dissections for T1/T2N0M0 BCAC would reduce the morbidity associated with the treatment of this rare parotid tumor.

Clinical utility of anaerobic culture of cerebrospinal fluid.

Anaerobic meningitis is a rare serious clinical condition which mainly affects vulnerable populations and patients with predisposing factors such as head trauma, prior neurosurgical procedures or implantable medical devices such as ventriculoperitoneal shunts or ventricular drains. In this study we retrieved data from aerobic and anaerobic cultures of cerebrospinal (CSF) or ventricular fluid ordered over a 5 year period at our institution. A total of 8868 aerobic and 594 anaerobic cultures were performed from 2013 to 2017. 24/594 (4%) anaerobic cultures from 14 patients were positive for anaerobes. Only 3 of those patients were diagnosed clinically with anaerobic meningitis, each with predisposing factors, while anaerobes (Cutibacterium acnes and Clostridium perfringens) recovered from the remaining 21 patients were regarded as contaminants. 129/8868 (1.45%) aerobic CSF cultures were positive for anaerobes. 120/129 (93%) cultures recovered C. acnes while non-C. acnes anaerobes were recovered in the remaining 9 cultures and were deemed to be contaminants. In the majority of situations, recovery of C. acnes from CSF or ventricular fluid was regarded as contamination. Our cohort included 18 patients with a ventriculoperitoneal shunt or ventricular drain, 17 of whom had C. acnes recovered from either aerobic or anaerobic culture, and 10 were treated with targeted antibiotics and surgical replacement of the shunt or drain. Anaerobic culture of the CSF or ventricular fluid aided in identification of two patients with anaerobic meningitis and an additional two patients with shunt infection. Anaerobe culture of CSF is important in identification of anaerobic meningitis, as growth of anaerobes other than C. acnes is rare from aerobic CSF culture.

Formalin pigment artifact deposition in autopsy tissue: predisposing factors, patterns of distribution and methods for removal.

Formalin pigment deposition is a known artifact of autopsy histology, often anecdotally associated with decomposition of bodies. However, there is minimal data within the forensic literature demonstrating an association between formalin pigment deposition and length of postmortem interval. Furthermore, there is minimal data concerning other predisposing factors and patterns of distribution of formalin pigment deposition. In this study, we compare the amount and patterns of formalin deposition on histology slides from three categories of death: 1) decomposed bodies, 2) critically ill at time of death, and 3) sudden cardiac death. We also compare the effectiveness of two relatively simple histology laboratory methods to remove formalin pigment deposition from histology slides. Amongst the three categories of death, formalin deposition was highest in the decomposed category, second highest in the critically ill category, and lowest in the sudden cardiac death category. The organs most severely affected by formalin deposition were liver/spleen/pancreas and kidneys, and the organs least affected were brain and lung. Formalin pigment deposition correlated with length of postmortem interval. Histologic patterns of formalin deposition included the endothelial lining of vessels, perinuclear compartment of neurons and myocytes, and the basal epithelial compartment of renal tubular epithelial cells. The alcoholic ammonium hydroxide method (AAH) was slightly more effective than the alkylphenol ethoxylate (APE) method for removing formalin pigment, though both methods were effective. Because formalin pigment is strongly refractile under polarized light, a polarization filter can also be useful for distinguishing formalin pigment from other pigments.

Loss of succinate dehydrogenase B immunohistochemical expression distinguishes pulmonary chondromas from hamartomas.

AIMS: Pulmonary chondromas, which are rare cartilaginous neoplasms that often arise in the setting of Carney triad, are morphologically similar to pulmonary hamartomas, which are much more common. There is evidence that succinate dehydrogenase (SDH) deficiency drives neoplasia in patients with Carney triad, and SDHB immunohistochemistry can be used as a surrogate marker to detect SDH deficiency. The aim of this study was to investigate the utility of SDHB immunohistochemistry in distinguishing pulmonary chondromas from hamartomas. METHODS AND RESULTS: Immunohistochemistry for SDHB (clone 21A11AE7) was performed on histological sections from six cases of pulmonary chondroma and 33 cases of pulmonary hamartoma. SDHB expression was retained in all 33 pulmonary hamartomas, and lost in the majority of evaluable chondromas (five of six). Of the five patients with chondromas showing SDHB loss, four had definitive Carney triad. Most patients with pulmonary hamartomas were older males with small solitary masses, whereas chondromas often presented as multiple masses in young females. CONCLUSION: Loss of SDHB immunohistochemical expression can be useful for differentiating pulmonary chondromas from hamartomas, and potentially identifying patients with Carney triad.

CD206-positive myeloid cells bind galectin-9 and promote a tumor-supportive microenvironment.

In patients with metastatic melanoma, high blood levels of galectin-9 are correlated with worse overall survival and a bias towards a Th2 inflammatory state supportive of tumor growth. Although galectin-9 signaling through TIM3 on T cells has been described, less is known about the interaction of galectin-9 with macrophages. We aimed to determine whether galectin-9 is a binding partner of CD206 on macrophages and whether the result of this interaction is tumor-supportive. It was determined that incubation of CD68+ macrophages with galectin-9 or anti-CD206 blocked target binding and that both CD206 and galectin-9 were detected by immunoprecipitation of cell lysates. CD206 and galectin-9 had a binding affinity of 2.8 × 10-7  m. Galectin-9 causes CD206+ macrophages to make significantly more FGF2 and monocyte chemoattractant protein (MCP-1), but less macrophage-derived chemokine (MDC). Galectin-9 had no effect on classical monocyte subsets, but caused expansion of the non-classical populations. Lastly, there was a positive correlation between increasing numbers of CD206 macrophages and galectin-9 expression in tumors, and high levels of CD206 macrophages correlated negatively with melanoma survival. These results indicate that galectin-9 binds to CD206 on M2 macrophages, which appear to drive angiogenesis and the production of chemokines that support tumor growth and poor patient prognoses. Targeting this interaction systemically through circulating monocytes may therefore be a novel way to improve local anti-tumor effects by macrophages. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Tunica Vaginalis Thickening, Hemorrhagic Infiltration and Inflammatory Changes in 8 Children with Primary Hydrocele; Reactive Mesothelial Hyperplasia? A Prospective Clinical Study.

The aim of this study is to describe an entity of primary hydrocele accompanied with fibrosis, thickening and hemorrhagic infiltration of parietal layer of tunica vaginalis (PLTV). During a 4-year period (2011-2014), 94 boys (2.5-14 years old) underwent primary hydrocele repair. Hydrocele was right sided in 55 (58.5 %), left sided in 26 (28.7%) and bilateral in 12 patients (13.8%). Eighty three out of 94 patients (88.30%) had communicating hydrocele and the rest eleven patients (11.7%) had non-communicating. Our case group consists of 8 patients (8.51%) based on operative findings consistent with PLTV induration, thickening and hemorrhagic infiltration. Preoperative ultrasonography did not reveal any pathology of the intrascrotal structures besides hydrocele. There weren't hyperechoic reflections or septa within the fluid. Evaluation of thickness of the PLTV was not feasible. Presence of lymph or exudate was excluded after fluid biochemical analysis. Tunica vaginalis histological examination confirmed thickening, hemorrhagic infiltration and inflammation, while there was absence of mesothelial cells. Immunochemistry for desmin was positive, excluding malignant mesothelioma. One patient underwent high ligation of the patent processus vaginalis and PLTV sheath fenestration, but one year later, he faced a recurrence. An elective second surgery was conducted via scrotal incision and Jaboulay operation was performed. The latter methodology was our treatment choice in other 7 out of 8 patients. During a 2-year postoperative follow-up, no other patient had any recurrence. We conclude that in primary hydrocele with macroscopic features indicative of tunica vaginalis inflammation, reversion of the tunica should be a part of operative strategy instead of sheath fenestration, in order to minimize the recurrence.

Covered perforation of Meckel's diverticulum ulcer to transverse colon: highlighting the urgent intervention and the avoidance of a dramatic evolution (case report and literature review).

Meckel's diverticulum represents a remnant of the proximal end of the omphalomesenteric duct, which constitutes a connection between the middle intestine and the vitelline vesicle. It is the most common congenital anomaly of the gastrointestinal tract and is found in approximately 0.3-2% of the general population. Complications such as hemorrhage, bowel obstruction, inflammation, perforation, intussusception, volvulus and malignant transformation develop in only 4-4.8% of all patients, with most cases presenting in childhood, while relative risk decreases during life. The aim of the present study is to present our experience in managing a 15-year old male patient with Meckel's diverticulum covered perforation. It was a case of disguised perforation of the Meckel's diverticulum, with development of adhesions to the anterior surface of the right third of the transverse colon, which was successfully treated on the basis of emergency. Diagnosis was made intraoperatively and was documented by histological examination of the excised diverticulum.

Canaliform median raphe cysts (MRCs) lined by squamous epithelium in a 5 year old male patient; report of a rare case and comprehensive review of the literature.

Median raphe cysts (MRCs) are rare, benign congenital lesions of unknown origin, that can be found anywhere on the ventral side of the genital area, between the urethral meatus and the anus. The rarity of our case is attributed to the canaliform type, the scrotal and perineal localization and the epidermoid epithelium. A 5 year old boy, with free perinatal and family history, was admitted to our department as an outpatient due to the presence of an elongated and mildly painful lesion in the middle of the scrotum, gradually increasing in size. During physical examination the presence of a painful, subcutaneous, yellowish lesion, extending from the scrotal to the perineal raphe, was documented. Patient underwent elective surgery, under general endotracheal anesthesia, and complete resection of the lesion was conducted. Histopathological examination revealed the presence of a canaliform lesion consisting of five cysts, lined by squamous epithelium and filled with lamellate keratin. IN CONCLUSION: a) preventive removal of MRCs is considered as the safest treatment option, in order to be avoided future, potential complications regarding urination and sexual intercourse, b) if therapeutic intervention is delayed, especially a er development of inflammation of MRCs, then the likelihood both of iatrogenic injury to underlying structures, mainly to the penile or perineal urethra, and of relapse a er resection increases significantly and c) if orchidopexy precedes the development of MRCs, the possibility of presence of ovarian serous border line tumor with Müllerian duct remnants should always be excluded.

Spitz Melanocytic Tumors: A Fascinating 75-Year Journey.

Over the last 75 years, our understanding of Spitz lesions has undergone substantial evolution. Initially considered a specific type of melanoma, the perception has shifted towards recognizing Spitz lesions as a spectrum comprising Spitz nevi, Spitz melanocytomas, and Spitz melanomas. Spitz lesions are known for posing a significant diagnostic challenge regarding the distinction between benign neoplasms displaying atypical traits and melanomas. A comprehensive understanding of their molecular basis and genomic aberrations has significantly improved precision in classifying and diagnosing these challenging lesions. The primary aim of this review is to encapsulate the current understanding of the molecular pathogenesis and distinct clinicopathologic characteristics defining this intriguing set of tumors.

RET splice site variants in medullary thyroid carcinoma.

Introduction: Medullary thyroid carcinoma (MTC) is an aggressive cancer that is often caused by driver mutations in RET. Splice site variants (SSV) reflect changes in mRNA processing, which may alter protein function. RET SSVs have been described in thyroid tumors in general but have not been extensively studied in MTC. Methods: The prevalence of RET SSVs was evaluated in 3,624 cases with next generation sequence reports, including 25 MTCs. Fisher exact analysis was performed to compare RET SSV frequency in cancers with/without a diagnosis of MTC. Results: All 25 MTCs had at least one of the two most common RET SSVs versus 0.3% of 3,599 cancers with other diagnoses (p < 0.00001). The 11 cancers with non-MTC diagnoses that had the common RET SSVs were 4 neuroendocrine cancers, 4 non-small cell lung carcinomas, 2 non-MTC thyroid cancers, and 1 melanoma. All 25 MTCs analyzed had at least one of the two most common RET SSVs, including 4 with no identified mutational driver. Discussion: The identification of RET SSVs in all MTCs, but rarely in other cancer types, demonstrates that these RET SSVs distinguish MTCs from other cancer types. Future studies are needed to investigate whether these RET SSVs play a pathogenic role in MTC.

Immunohistochemical expression of carbonic anhydrase 9, glucose transporter 1, and paired box 8 in von Hippel-Lindau disease-related lesions.

von Hippel-Lindau (VHL) disease occurs secondary to pathogenic alterations of the VHL tumor suppressor gene, manifesting with cysts and tumors in multiple organ systems. VHL protein (pVHL) is a known downregulator of hypoxia inducible factor-1a (HIF1a). Loss of function of pVHL is associated with upregulation of the HIF1a pathway including carbonic anhydrase 9 (CA9) and glucose transporter 1 (GLUT1). Paired box 8 (PAX8) is an important transcription factor regulator of mesonephric development. We investigated the role of immunohistochemistry in the assessment of CA9, GLUT1, and PAX8 expression in VHL disease-related lesions. Clinicopathologic information and archived pathology material from 5 patients with VHL disease were reviewed and evaluated for expression of CA9, GLUT1, and PAX8. The spectrum of VHL disease-related lesions included hemangioblastoma, endolymphatic sac tumor, pulmonary microcysts, pheochromocytoma, pancreatic neuroendocrine tumor and serous cystadenoma, renal cysts, renal cell carcinoma, and epididymal papillary cystadenoma. CA9 was expressed in all lesions and exhibited diffuse positivity (15/15 lesions, 100%; 5/5 patients), while GLUT1 expression was focal/weak or absent in some instances (strong positive: 12/15 lesions, 80%; 5/5 patients). PAX8 was expressed only in renal and epididymal lesions. CA9 and GLUT1 are consistently overexpressed in VHL disease-related lesions, reflecting upregulation of the HIF1a pathway. PAX8 is only expressed in genitourinary lesions, mirroring organ-specific differentiation. A combination of CA9 and GLUT1 immunostains is useful in screening lesions of patients with VHL spectrum manifestations, which may be targeted by the recently Food and Drug Administration-approved HIF-2a inhibitors.

Clinical Significance of Major Angiogenesis-Related Effectors in Patients with Metastatic Breast Cancer Treated with Trastuzumab-Based Regimens.

PURPOSE: Angiogenesis is a crucial phenomenon in the development and progression of breast cancer (BC), but the clinical significance of angiogenesis-related proteins in metastatic BC remains unknown. This study investigates the prognostic value of vascular endothelial growth factor receptors 1, 2, 3 (VEGFR1, VEGFR2, VEGFR3) as well as vascular endothelial growth factors A and C (VEGFA and VEGFC) in metastatic BC patients treated with trastuzumab-based regimens. MATERIALS AND METHODS: Two hundred female patients were included. Protein and mRNA expression of the studied angiogenesis-related factors were evaluated by immunohistochemistry and quantitative polymerase chain reaction, respectively. RESULTS: High expression of VEGFA, VEGFC, VEGFR1, VEGFR2, and VEGFR3 in the tumor cells was observed in 43.5%, 24.2%, 36%, 29.5%, and 43%, respectively. Stromal elements expressed high levels of VEGFA, VEGFC, VEGFR1, VEGFR2, and VEGFR3 in 78.9%, 93.3%, 90.7%, 90.2%, and 74.8% of tumors with available data. High tumor cell expression of VEGFR1 was a favorable prognosticator for survival among patients with human epidermal growth factor receptor 2 (HER2)-positive tumors (hazard ratio [HR], 0.55; p=0.013). A trend towards longer progression-free survival was detected univariately for patients with HER2-negative tumors and high expression of VEGFR2 (HR, 0.60; p=0.059). CONCLUSION: VEGFR1 and VEGFR2 seem to have significant prognostic value in BC patients with metastatic disease treated with trastuzumab-based regimens.

Investigation of prognostic biomarkers in patients with urothelial carcinoma treated with platinum-based regimens.

BACKGROUND: Bladder cancer (BC) is a heterogeneous malignancy with dismal outcome. PATIENTS AND METHODS: Mutations in genes, altered or linked to platinum sensitivity in BC, were examined in 66 patients' tumors along with tumor infiltrating lymphocytes (TILs) density and MMR, PD-L1 and CD8 protein expression, as well as basal and luminal subtypes, defined by protein expression of markers, including CK5/6 and GATA3 or CK20, respectively. RESULTS: 41 tumors harbored mutations, mainly in TP53 (38%), ARID1A (17%) and the DNA damage response and repair (DDR) genes ERCC2 (17%) and BRCA2 (15%). Mutations in other DDR relevant genes were also present. Age showed unfavorable prognosis for overall survival (HR=1.07, P = 0.026); no benefit was seen for patients with TP53, ARID1A, ERCC2 or BRCA2 mutations or mutations in 1 or more DDR genes. PD-L1 status positively correlated with stromal (rho=0.46, P < 0.001) and intratumoral (rho=0.53, P < 0.001) CD8 expression or TILs (rho=0.29, P = 0.018); none associated with overall survival (OS). A statistically significant difference was observed between PD-L1 status and immunohistochemistry (IHC)­based subtypes, with tumors classified as luminal (GATA3+ and/or CK20+ and CK5/6-) showing lower PD-L1 expression relative to basal (CK5/6+ and GATA3- and/or CK20-) (median value 0 vs. 2.5, P = 0.029). Concerning OS, no statistically significant difference was seen among patients with basal or luminal tumors. CONCLUSION: No association was seen herein between DDR mutations, TILs, PD-L1, CD8 expression or IHC-based subtypes and patient survival; these observations warrant validation within a larger cohort.