Outcomes in solid organ transplant recipients receiving organs from a donor with Fusarium solani species complex meningitis.

BACKGROUND: Five organs (heart, right lung, liver, right, and left kidneys) from a deceased patient were transplanted into five recipients in four US states; the deceased patient was identified as part of a healthcare-associated fungal meningitis outbreak among patients who underwent epidural anesthesia in Matamoros, Mexico. METHODS: After transplant surgeries occurred, Fusarium solani species complex, a fungal pathogen with a high case-mortality rate, was identified in cerebrospinal fluid from the organ donor by metagenomic next-generation sequencing (mNGS) and fungal-specific polymerase chain reaction and in plasma by mNGS. RESULTS: Four of five transplant recipients received recommended voriconazole prophylaxis; four were monitored weekly by serum (1-3)-ß-d-glucan testing. All five were monitored for signs of infection for at least 3 months following transplantation. The liver recipient had graft failure, which was attributed to an etiology unrelated to fungal infection. No fungal DNA was identified in sections of the explanted liver, suggesting that F. solani species complex did not contribute to graft failure. The remaining recipients experienced no signs or symptoms suggestive of fusariosis. CONCLUSION: Antifungal prophylaxis may be useful in preventing donor-derived infections in recipients of organs from donors that are found to have Fusarium meningitis.

Comparative analysis of PD-L1 expression and tumor-infiltrating lymphocytes in metaplastic breast carcinoma and gynecologic carcinosarcoma: A single-institution retrospective study.

Metaplastic breast carcinoma (MBC) and gynecologic carcinosarcoma (GCS) are rare, clinically aggressive cancers that demonstrate epithelial components and mesenchymal or sarcomatoid components. In this study, we assessed PD-L1 expression and tumor-infiltrating lymphocytes (TILs) in MBC and GCS. Overall, PD-L1 positivity using the SP142 clone was seen in 50 % of MBC and 51.9 % of GCS cases, with PD-L1 expression in tumor cells significantly higher in MBC cases (p = 0.034), and PD-L1 expression in immune cells similar in MBC and GCS cases. PD-L1 expression was significantly higher in epithelial components than in mesenchymal components in both MBC and GCS cases (p = 0.0005). TILs were low in the majority of MBC and GCS cases (≥ 10 %) and generally correlated with PD-L1 expression; however, many PD-L1 positive cases with low TILs were seen. PD-L1 expression using the 22C3 clone was additionally assessed, with positivity seen in 62.9 % of MBC cases and 30 % of GCS cases. Concordance between SP142 and 22C3 results was seen in 62.5 % of MBC cases and 80 % of GCS cases. Overall, our findings suggest that a subset of MBC and GCS cases may benefit from immune checkpoint inhibitor therapy. Our findings also illustrate unique aspects of PD-L1 expression patterns in these tumors which may harbor additional prognostic and therapeutic significance.

Case of recurrent superficial CD34-positive fibroblastic tumor.

Superficial CD34-positive fibroblastic tumor (SCPFT) is a recently described rare superficial mesenchymal tumor. SCPFT has a distinctive morphologic appearance, marked by significant nuclear pleomorphism, low mitotic rate, and diffuse CD34 positivity. SCPFT is underdiagnosed because of its rarity and misdiagnosis as sarcoma, with very few reported cases of local recurrence or metastasis. Recognition and awareness of SCPFT are essential for accurate diagnosis and appropriate clinical management. We describe here the case of a 37-year-old male who presented with a right calf mass diagnosed as SCPFT with subsequent local recurrence of the tumor.

Superficial CD34-positive fibroblastic tumor (SCPFT): A review of pathological and clinical features.

Superficial CD34-positive fibroblastic tumor (SCPFT) is a recently described rare mesenchymal tumor of borderline malignancy. It generally involves superficial soft tissue, with a predilection to the lower extremities. Microscopically this tumor is characterized by a fascicular and storiform growth pattern, spindled to epithelioid cells, nuclear atypia with pleomorphism, and eosinophilic granular, and fibrillar to glassy cytoplasm. Strong diffuse immunoreactivity for CD34 is very characteristic of this entity. Due to under-recognition, this tumor is generally underreported. Additionally, cases of recurrence are rarely reported in the literature. We will comprehensively review the English language literature on all reported cases of SCPFT, with emphasis on recurrence.

Treatment of Coronavirus Disease 2019 (COVID-19) Patients with Convalescent Plasma.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, has spread globally, and no proven treatments are available. Convalescent plasma therapy has been used with varying degrees of success to treat severe microbial infections for >100 years. Patients (n = 25) with severe and/or life-threatening COVID-19 disease were enrolled at the Houston Methodist hospitals from March 28, 2020, to April 14, 2020. Patients were transfused with convalescent plasma, obtained from donors with confirmed severe acute respiratory syndrome coronavirus 2 infection who had recovered. The primary study outcome was safety, and the secondary outcome was clinical status at day 14 after transfusion. Clinical improvement was assessed on the basis of a modified World Health Organization six-point ordinal scale and laboratory parameters. Viral genome sequencing was performed on donor and recipient strains. At day 7 after transfusion with convalescent plasma, nine patients had at least a one-point improvement in clinical scale, and seven of those were discharged. By day 14 after transfusion, 19 (76%) patients had at least a one-point improvement in clinical status, and 11 were discharged. No adverse events as a result of plasma transfusion were observed. Whole genome sequencing data did not identify a strain genotype-disease severity correlation. The data indicate that administration of convalescent plasma is a safe treatment option for those with severe COVID-19 disease.

The impact of HER2-directed targeted therapy on HER2-positive DCIS of the breast.

BACKGROUND: In invasive breast cancer, HER2 is a well-established negative prognostic factor. However, its significance on the prognosis of ductal carcinoma in situ (DCIS) of the breast is unclear. As a result, the impact of HER2-directed therapy on HER2-positive DCIS is unknown and is currently the subject of ongoing clinical trials. In this study, we aim to determine the possible impact of HER 2-directed targeted therapy on survival outcomes for HER2-positive DCIS patients. MATERIALS AND METHODS: The National Cancer Data Base (NCDB) was used to retrieve patients with biopsy-proven DCIS diagnosed from 2004-2015. Patients were divided into two groups based on the adjuvant therapy they received: systemic HER2-directed targeted therapy or no systemic therapy. Statistics included multivariable logistic regression to determine factors predictive of receiving systemic therapy, Kaplan-Meier analysis to evaluate overall survival (OS), and Cox proportional hazards modeling to determine variables associated with OS. RESULTS: Altogether, 1927 patients met inclusion criteria; 430 (22.3%) received HER2-directed targeted therapy; 1497 (77.7%) did not. Patients who received HER2-directed targeted therapy had a higher 5-year OS compared to patients that did not (97.7% vs. 95.8%, p = 0.043). This survival benefit remained on multivariable analysis. Factors associated with worse OS on multivariable analysis included Charlson-Deyo Comorbidity Score ≥ 2 and no receipt of hormonal therapy. CONCLUSION: In this large study evaluating HER2-positive DCIS patients, the receipt of HER2-directed targeted therapy was associated with an improvement in OS. The results of currently ongoing clinical trials are needed to confirm this finding.

Lesions of anogenital mammary-like glands: Four cases including novel pathologic and immunohistochemical observations.

Anogenital mammary-like glands, formerly described as ectopic breast tissue, are currently considered to be normal histologic components of the anogenital region. Anogenital mammary-like glands can give rise to many lesions identical to counterparts in the native female breast. We describe four cases of such lesions, including fibroadenoma, gynecomastia-like hyperplasia, and ectopic mammary-type tissue with a spectrum of usual ductal hyperplasia, apocrine metaplasia, adenosis, and pseudolactational change. All four cases occurred in young women (ages 29-38) who presented with vulvar or perianal masses. Similar to previously reported cases, these lesions shared histologic and immunohistochemical characteristics identical to native female breast lesions. Novel findings in our cases included (1) the first case of gynecomastia-like change to be reported in the perianal area of a female, (2) Immunohistochemical staining identifying a 3-layered epithelium characterized by a population of CK14 and CK5/6 positive and hormone receptor negative superficial luminal cells, and (3) diffuse, strong positivity for GATA3 in all cases. Our study adds to the literature on these rare lesions and highlights findings which may be useful in understanding the pathogenesis and improving the diagnosis of anogenital mammary-like gland lesions.

A randomized, controlled phase II trial of neoadjuvant ado-trastuzumab emtansine, lapatinib, and nab-paclitaxel versus trastuzumab, pertuzumab, and paclitaxel in HER2-positive breast cancer (TEAL study).

BACKGROUND: Neoadjuvant dual human epidermal growth factor receptor (HER2) blockade with trastuzumab and pertuzumab plus paclitaxel leads to an overall pathologic complete response (pCR) rate of 46%. Dual HER2 blockade with ado-trastuzumab emtansine (T-DM1) and lapatinib plus nab-paclitaxel has shown efficacy in patients with metastatic HER2-positive breast cancer. To test neoadjuvant effectiveness of this regimen, an open-label, multicenter, randomized, phase II trial was conducted comparing T-DM1, lapatinib, and nab-paclitaxel with trastuzumab, pertuzumab, and paclitaxel in patients with early-stage HER2-positive breast cancer. METHODS: Stratification by estrogen receptor (ER) status occurred prior to randomization. Patients in the experimental arm received 6 weeks of targeted therapies (T-DM1 and lapatinib) followed by T-DM1 every 3 weeks, lapatinib daily, and nab-paclitaxel weekly for 12 weeks. In the standard arm, patients received 6 weeks of trastuzumab and pertuzumab followed by trastuzumab weekly, pertuzumab every 3 weeks, and paclitaxel weekly for 12 weeks. The primary objective was to evaluate the proportion of patients with residual cancer burden (RCB) 0 or I. Key secondary objectives included pCR rate, safety, and change in tumor size at 6 weeks. Hypothesis-generating correlative assessments were also performed. RESULTS: The 30 evaluable patients were well-balanced in patient and tumor characteristics. The proportion of patients with RCB 0 or I was higher in the experimental arm (100% vs. 62.5% in the standard arm, p = 0.0035). In the ER-positive subset, all patients in the experimental arm achieved RCB 0-I versus 25% in the standard arm (p = 0.0035). Adverse events were similar between the two arms. CONCLUSION: In early-stage HER2-positive breast cancer, the neoadjuvant treatment with T-DM1, lapatinib, and nab-paclitaxel was more effective than the standard treatment, particularly in the ER-positive cohort. TRIAL REGISTRATION: Clinicaltrials.gov NCT02073487 , February 27, 2014.

Role of HPV genotyping in risk assessment among cytology diagnosis categories: analysis of 4562 cases with cytology-HPV cotesting and follow-up biopsies.

OBJECTIVE: Human papilloma virus (HPV) detection and genotyping are increasingly used in clinical risk assessment. We aimed to analyze HPV genotyping performance in risk stratification among cytology diagnosis categories. METHODS: Between January 1, 2015 and December 31, 2016, 4562 cases with cytology-HPV co-testing and biopsy follow-up were identified. HPV tests were performed on Cobas (n=3959) or Aptima (n=603) platforms. Of the biopsies, 669 demonstrated high-grade squamous intraepithelial lesions or worse. RESULTS: Pooled high-risk HPV testing had high overall sensitivity (97%) but low specificity (20%) and positive predictive value (20%) for biopsy-confirmed high-grade squamous intraepithelial lesions or worse. HPV16/18 genotyping had considerably improved specificity (81%) and positive predictve value (35%) in predicting high-grade squamous intraepithelial lesions or worse, especially in atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesion categories. Significantly more biopsy-confirmed high-grade squamous intraepithelial lesions or worse were detected by Aptima than Cobas testing, as measured by HPV16/18 (48% vs 33%, p<0.001), non-16/18 high-risk HPV (18% vs 13%, p=0.029), or all high-risk HPV genotypes (27% vs 19%, p<0.001). Aptima genotyping showed a significantly higher positive predictive value than Cobas genotyping for biopsy-confirmed high-grade squamous intraepithelial lesions or worse in the atypical squamous cells of undetermined significance category (47% vs 23%, p<0.05). CONCLUSIONS: HPV genotyping was sensitive for biopsy-confirmed high-grade squamous intraepithelial lesions or worse in all cytologic categories, and is particularly valuable in risk evaluation for women with atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesions. The triaging role was greatly diminished in high-risk lesions (atypical glandular cells, atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesions and high-grade squamous intraepithelial lesions) due to low specificity and positive predictive value. Aptima performance in risk management was superior to Cobas, with significantly higher positive predictive value for biopsy-confirmed high-grade squamous intraepithelial lesions or worse. Our results highlight the importance of careful data interpretation from studies using different HPV testing methods and the need to incorporate HPV E6/E7-mRNA testing into management guidelines.

The impact of molecular status on survival outcomes for invasive micropapillary carcinoma of the breast.

Invasive micropapillary carcinoma (IMPC) is an uncommon variant of breast cancer. Previous studies demonstrated this subtype is often hormone receptor (HR)-positive, resulting in survival outcomes similar to invasive ductal carcinoma. However, many of these studies were conducted prior to HER2 testing availability. We aim to determine the impact of molecular marker status (including HER2 status) on IMPC survival outcomes. The National Cancer Data Base (NCDB) was used to retrieve patients with biopsy-proven IMPC from 2007 to 2012. Only patients with known HR and HER2 status were included. Cox multivariate regression was used to determine prognostic factors. In total, 865 patients were included; median follow-up was 2.5 years. Overall, 651 patients (75.3%) had HR + HER2- disease, 128 (14.8%) had HR + HER2+ disease, 41 (4.7%) had HR-HER2 + disease, and 45 (5.2%) had triple negative disease. Patients with triple negative disease were more likely to have poorly differentiated histology (66.7%), lymphovascular invasion (73.3%), stage 3 disease (37.8%), undergone mastectomy (68.9%), and positive surgical margins (15.6%). On Cox multivariate regression, those with triple negative disease had worse overall survival (hazard ratio [HR] 7.28, P < 0.001). Other adverse prognostic factors included African-American descent (HR 2.24, P = 0.018), comorbidity score of 1 (HR 2.50, P = 0.011), comorbidity score ≥2 (HR 3.27, P = 0.06), and ≥3 positive lymph nodes (HR 3.23, P = 0.007). Similar to invasive ductal carcinoma, triple negative disease in IMPC results in worse survival outcomes. This is the largest and first study to characterize molecular status (including HER2 status) in patients with IMPC and its impact on survival outcomes.

Flat epithelial atypia in directional vacuum-assisted biopsy of breast microcalcifications: surgical excision may not be necessary.

The aim of this study was to analyze the clinicopathological features of patients with flat epithelial atypia, diagnosed in directional vacuum-assisted biopsy targeting microcalcifications, to identify upgrade rate to in situ ductal or invasive breast carcinoma, and determine factors predicting carcinoma in the subsequent excision. We retrospectively evaluated the histological, clinical, and mammographic features of 69 cases from 65 women, with directional vacuum-assisted biopsy-diagnosed flat epithelial atypia with or without atypical ductal hyperplasia or atypical lobular hyperplasia, which underwent subsequent surgical excision. The extent and percentage of microcalcifications sampled by directional vacuum-assisted biopsy were evaluated by mammography. All biopsy and surgical excision slides were reviewed. The age of the women ranged from 40 to 85 years (mean 57 years). All patients presented with mammographically detected microcalcifications only, except in one case that had associated architectural distortion. Extent of calcifications ranged from <1 cm (n = 47), 1-3 cm (n = 15) to > 3 cm (n = 6), and no measurement (n = 1). A mean of 11 cores (range 6-25) was obtained from each lesion. Post-biopsy mammogram revealed >90% removal of calcifications in 81% of cases. Pure flat epithelial atypia represented nearly two-thirds of directional vacuum-assisted biopsy specimens (n = 43, 62%), while flat epithelial atypia coexisted with atypical ductal hyperplasia (18 cases, 26%), or atypical lobular hyperplasia (8 cases, 12%). Upon excision, none of the cases were upgraded to in situ ductal or invasive breast cancer. In one case, however, an incidental, tubular carcinoma (4 mm) was found away from biopsy site. Excluding this case, the upgrade rate was 0%. Our study adds to the growing evidence that diagnosis of flat epithelial atypia on directional vacuum-assisted biopsy for microcalcifications as the only imaging finding is not associated with a significant upgrade to carcinoma on excision, and therefore, excision may not be necessary. Additionally, excision may not be necessary for flat epithelial atypia with atypical ductal hyperplasia limited to ≤2 terminal duct-lobular units, if at least 90% of calcifications have been removed on biopsy.

Clinical presentation of ductal carcinoma in situ of breast with intraluminal crystalloids: Radiologic-histologic correlation.

Intraluminal crystalloids have rarely been described in the breast, particularly in cases with ductal carcinoma in situ (DCIS). We recently encountered a case of DCIS of the breast associated with numerous intraluminal crystalloids. The patient presented with a mass in the right breast, and microcalcifications were detected on screening and diagnostic mammograms; the patient underwent needle biopsies, lumpectomy, and skin-sparing mastectomy. Invasive ductal carcinoma associated with extensive DCIS was diagnosed. Multiple refractile, eosinophilic crystalloids, with variable morphologies including rectangular, triangular and needle-like with sharp borders, were observed within the lumina of DCIS, besides calcium phosphate microcalcifications. We report this case together with a literature review on crystalloid-containing lesions in breast and non-breast tissues. We also studied radiologic findings of these crystalloids using a specimen radiograph.

Aptima Human Papillomavirus E6/E7 mRNA Test Results Strongly Associated With Risk for High-Grade Cervical Lesions in Follow-Up Biopsies.

OBJECTIVE: Human papillomavirus (HPV) tests and genotyping (GT) have been used in clinical risk assessment. The purpose of this study was to analyze the performance of 2 common HPV testing platforms in risk evaluation for high-grade cervical lesions. MATERIALS AND METHODS: Between January 1, 2015, and December 31, 2016, a total of 4,562 Pap tests with follow-up biopsies in our laboratory database were analyzed along with HPV tests performed on Cobas (CHPV, n = 3,959) or Aptima (AHPV, n = 603) platforms. RESULTS: The sensitivity for biopsy-confirmed HSIL or worse lesions was 97% for both CHPV and AHPV (p = .75). AHPV showed significantly lower positive rates than CHPV in benign (56% vs 86%) or LSIL (66% vs 90%) biopsies, resulting in significantly higher specificity for HSIL or worse than CHPV (38% vs 12%, p < .001). AHPV demonstrated significantly higher positive predictive value for HSIL or worse (24% vs 16%, p < .001) and overall accuracy (48% vs 24%, p < .001) than CHPV. AHPV GT also had significantly higher specificity for biopsy-confirmed HSIL or worse than CHPV (88% vs 72%, p < .001) with comparable sensitivity (50% vs 51%, p = .75). Women with HPV 16 on AHPV were significantly more likely to have HSIL or worse on biopsies than those with HPV 16 on CHPV (likelihood ratio = 4.3 vs 2.0, p = .004). CONCLUSIONS: Although both AHPV and CHPV were highly sensitive for biopsy-confirmed HSIL or worse lesions, AHPV and GT demonstrated significantly higher specificity and positive predictive value than CHPV. The difference is probably related to E6/E7 overexpression after viral DNA integration in high-grade lesions. The significantly higher specificity and overall accuracy of AHPV and GT for HSIL or worse lesions may be useful in clinical risk management.

Adverse tissue reactions after total hip arthroplasty.

Hip arthroplasty is commonly performed on patients with debilitating hip disease to relieve symptoms and improve quality of life. Generally, long-term success rates are excellent. However, a subset of patients requires revision due to prosthesis failure. A wide array of microscopic findings can be seen in surrounding tissues and many of the findings are etiologically nonspecific. The aim of this review is to discuss the etiologies and accompanying adverse tissue reactions seen with prosthesis failure, including the findings seen in aseptic lymphocyte-dominated vasculitis-associated lesion. Aseptic lymphocyte-dominated vasculitis-associated lesion is an important diagnostic consideration as its proposed pathogenesis is a type VI hypersensitivity response to metal ions. In addition, we also propose a diagnostic algorithm that incorporates clinical and histopathologic findings to suggest an etiologic cause. This proposed algorithm may be clinically useful as, to date, there is no consensus on nomenclature.

Atypical glandular cells in Pap tests: cytology-histology correlation and risk assessment with human papillopmavirus (HPV) testing.

INTRODUCTION: Atypical glandular cells (AGC) represent less than 1% of Pap test cases and include a variety of lesions in both the cervix and endometrium. The study aimed to investigate the cytology-histology correlation in AGC patients and to evaluate the clinical utility of hrHPV testing in this diagnostic context. MATERIALS AND METHODS: We identified 491 atypical glandular cells (AGC) cases in our quality analysis (QA) database of 336,064 Pap tests interpreted between March 1, 2013 and July 12, 2016. Of these, 251 cases had follow-up biopsies with hrHPV tests in 148 cases. RESULTS: The most common histologic diagnosis associated with AGC was normal/benign or low-grade lesions, comprising 55% of cervical biopsies and 24% of endometrial biopsies. High-grade lesions were identified in 21% of follow-up biopsies. In patients with AGC cytology, a positive hrHPV test significantly increased the likelihood of cervical HSIL or above lesions on biopsy by 26.4 times (OR = 26.4, 95% CI: 5.8-119.4, P < 0.0001). A positive genotyping result for HPV 16 dramatically increased the likelihood of cervical HSIL or above lesions on biopsy (OR = 84, 95% CI: 12.0-590.5, P < 0.0001). The HPV test had a negative predictive value of 97% (CI: 85%-100%). CONCLUSIONS: Our study confirms that AGC is a significant diagnosis with an overall risk for high-grade cervical or endometrial lesions as high as 21%. hrHPV testing with genotyping is an effective tool for identifying high-risk individuals within the AGC population, with excellent positive and negative predictive values. This approach is valuable for clinical risk stratification and differential diagnosis in patients with AGC cytology.

Role of 21-Gene Recurrence Score in Predicting Prognostic Benefit of Radiation Therapy After Breast-Conserving Surgery for T1N0 Breast Cancer.

PURPOSE: The 21-gene RT-PCR recurrence score (RS) is performed in patients with hormone receptor-positive (ER+, PR+), human epidermal growth factor receptor 2 (HER2)-negative, N0 breast cancer to determine which patients will likely benefit from chemotherapy after breast-conserving surgery (BCS). The purpose of this study was to evaluate whether the RS can predict for patients likely to benefit from radiation therapy (RT) after BCS. METHODS AND MATERIALS: The National Cancer Database was queried (2004-2017) for female patients with pT1N0 ER+ PR+ HER2-negative breast cancer treated with BCS who had an available RS. Patients were stratified based on their RS (low risk [LR], 1-10; intermediate risk [IR], 11-25; high risk [HR], 26-100). For each RS cohort, propensity score matching was conducted to create 1:1 matched cohorts of patients who received RT and patients who did not. Kaplan-Meier analysis evaluated overall survival (OS). Univariable and multivariable (MVA) Cox proportional hazard analysis identified clinical and treatment factors prognostic for OS. RESULTS: A total of 79,040 patients met the selection criteria: 18,823 in the LR cohort, 52,341 in the IR cohort, and 7876 in the HR cohort. A total of 92% of patients received RT: 91% in the LR cohort, 93% in the IR cohort, and 92% in the HR cohort. After propensity score matching, the 5-year OS in the LR cohort was 95% for those who received RT and 93% for those who did not (P = .184). In the IR cohort, the 5-year OS was 95% for those who received RT and 93% for those who did not (P = .001). In the HR cohort, the 5-year OS was 95% for those who received RT and 84% for those who did not (P < .001). MVA demonstrated that RT was a positive prognostic factor for OS in both the IR cohort (P = .001) and HR cohort (P < .001). On MVA in the LR cohort, RT (P = .186) was not predictive of improved OS. CONCLUSIONS: An OS benefit was observed with the use of RT in patients with IR or HR RS but not in patients with LR RS. Future prospective evaluation is warranted.

Comparison of breast carcinoma prognostic/predictive biomarkers on cell blocks obtained by various methods: Cellient, formalin and thrombin.

OBJECTIVE: To compare results of immunohistochemical (IHC) assays for estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) performed on thrombin, formalin and Cellient cell blocks to those performed on tissue. STUDY DESIGN: Formalin, thrombin and Cellient cell blocks were prepared from cytologic samples obtained from resection specimens of 31 patients with invasive breast carcinoma. ER, PR, HER2 and MIB-1 (Ki-67) IHC stains were performed on all three types of cell blocks and compared to the same stains performed on the patient's paraffin-embedded biopsy or resection. Cell and tissue blocks with equivocal staining for HER2 were submitted for fluorescence in situ hybridization (FISH). RESULTS: Adequate Cellient blocks were obtained for all 31 cases. Comparison of results of ER IHC assays on all three types of cell blocks showed 100% correlation with tissue. Both Cellient and thrombin blocks showed 100% correlation with tissue for HER2 IHC and FISH results. The only statistically significant difference between cell block methods was found in PR staining, where false-negative results occurred with Cellient and thrombin blocks. CONCLUSION: Breast biomarker IHC assays performed on Cellient blocks are reliable and correlate with tissue block results, particularly for ER and HER2, the most clinically important markers.