Vighnesh Walavalkar

Hyperprogressors after immunotherapy: Analysis of genomic alterations associated with accelerated growth rate

Purpose: Checkpoint inhibitors demonstrate salutary anticancer effects, including long-term remissions. PD-L1 expression/amplification, high mutational burden, and mismatch repair deficiency correlate with response. We have, however, observed a subset of patients who appear to be “hyperprogressors,” with a greatly accelerated rate of tumor growth and clinical deterioration compared with pretherapy, which was also recently reported by Institut Gustave Roussy. The current study investigated potential genomic markers associated with “hyperprogression” after immunotherapy. Experimental Design: Consecutive stage IV cancer patients who received immunotherapies (CTLA-4, PD-1/PD-L1 inhibitors or other [investigational] agents) and had their tumor evaluated by next-generation sequencing were analyzed (N = 155). We defined hyperprogression as time-to-treatment failure (TTF) <2 months, >50% increase in tumor burden compared with preimmunotherapy imaging, and >2-fold increase in progression pace. Results: Amongst 155 patients, TTF <2 months was seen in all six individuals with MDM2/MDM4 amplification. After anti-PD1/PDL1 monotherapy, four of these patients showed remarkable increases in existing tumor size (55% to 258%), new large masses, and significantly accelerated progression pace (2.3-, 7.1-, 7.2- and 42.3-fold compared with the 2 months before immunotherapy). In multivariate analysis, MDM2/MDM4 and EGFR alterations correlated with TTF <2 months. Two of 10 patients with EGFR alterations were also hyperprogressors (53.6% and 125% increase in tumor size; 35.7- and 41.7-fold increase). Conclusions: Some patients with MDM2 family amplification or EGFR aberrations had poor clinical outcome and significantly increased rate of tumor growth after single-agent checkpoint (PD-1/PD-L1) inhibitors. Genomic profiles may help to identify patients at risk for hyperprogression on immunotherapy. Further investigation is urgently needed. Clin Cancer Res; 23(15); 4242–50. ©2017 AACR.

Benign lymphoid aggregates in the bone marrow: Distribution patterns of B and T lymphocytes

Benign lymphoid aggregates are seen in only a minority of bone marrow specimens, but their distinction from non-Hodgkin lymphoma, particularly B-cell lymphomas, can represent a diagnostic challenge. Although criteria have been proposed to help distinguish between benign and malignant aggregates, a detailed description of the distribution patterns of B and T lymphocytes within benign lymphoid aggregates has not been investigated. One hundred thirty-seven cases of bone marrow specimens containing benign aggregates were studied with a panel of immunostains. A subset of these cases was also examined for immunoglobulin gene rearrangements by polymerase chain reaction. The aggregates were categorized based on size, location (paratrabecular or random), presence of infiltrating edges, and distribution of lymphoid cell populations. In addition, we examined 40 cases of bone marrow biopsies with documented malignant lymphoid aggregates for comparison purposes. We report that the distribution of B and T lymphocytes within lymphoid aggregates may serve as a useful criterion to aid in the separation between benign and malignant aggregates. When aggregates exhibit a predominance of T cells, consist of a central core of T cells surrounded by a rim of B cells, or have a mixed distribution of B and T cells, they are more likely to be benign. On the other hand, an increased likelihood of malignancy occurs when aggregates exhibit a predominance of B cells or consist of a central core of B cells surrounded by a rim of T cells (excluding germinal center formation), and assessing other features worrisome of malignancy (large aggregate size, presence of infiltrative edges, cellular atypia, and paratrabecular location, among others) is warranted.

CD4-positive T-cell primary central nervous system lymphoma in an HIV positive patient

OBJECTIVES Primary central nervous system lymphomas (PCNSLs) in patients with human immunodeficiency virus (HIV) are predominantly B-cell lymphomas associated with Epstein-Barr virus (EBV) and rarely CD8-positive T-cell PCNSLs. METHODS Patient history, laboratory results, cerebrospinal fluid (CSF), imaging, and brain biopsy specimens were reviewed and tested for T-cell receptor clonality. RESULTS A 64-year-old HIV-positive woman sought treatment for lethargy and left-sided weakness. Brain imaging showed regional increased T2 signal with restricted diffusion in cerebral hemispheres. CSF flow cytometry revealed CD4-positive T lymphocytes with loss of CD3, CD5, and CD7. EBV-positive T-cell lymphoma was immunohistochemically confirmed on brain biopsy specimens. Molecular analysis detected clonal T-cell receptor gene rearrangement. The patient received intrathecal methotrexate and whole-brain radiation. She did not respond to treatment and was eventually placed in hospice care. CONCLUSIONS To our knowledge, this is the first report of CD4-positive T-cell PCNSL in an HIV-positive patient and will help to raise clinical awareness of this previously unknown entity.

Evidence for increasing usage of low-grade squamous intraepithelial lesion, cannot exclude high-grade squamous intraepithelial lesion (LSIL-H) Pap test interpretations

Pap test (PT) interpretations of low‐grade squamous intraepithelial lesion (LSIL), cannot exclude high‐grade squamous intraepithelial lesion (HSIL), or LSIL‐H, are used in many laboratories; however monitoring its usage for quality assurance purposes is understudied.

Cytologic Diagnosis of Metastatic Alveolar Rhabdomyosarcoma to the Thyroid Gland by Fine-Needle Aspiration

Background: Metastases to the thyroid gland, although rare, are important entities to consider when evaluating malignant cells on a thyroid fine-needle aspiration (TFNA) specimen. Cellular TFNA specimens with small round blue cells should prompt a broad differential: florid lymphocytic thyroiditis, lymphoma, metastases, as well as primary thyroid malignancies with similar morphologies such as poorly differentiated (insular) and medullary carcinomas. Age, clinical presentation and prior history must be considered in every case. Case Report: We report, to the best of our knowledge, the first case of metastatic alveolar rhabdomyosarcoma (ARMS) to the thyroid gland, definitively diagnosed by TFNA. A 21-year-old female patient presented with a large mass in the right lobe of the thyroid. Her past history was significant for ARMS diagnosed 24 months earlier, currently in remission after successfully completing 40 weeks of chemoradiation therapy. The diagnosis of metastatic ARMS in the TFNA prompted a more thorough examination revealing previously unknown additional sites of metastases. Conclusion: Metastases to the thyroid gland are uncommon but should be considered in cases where atypical morphology is encountered. Small round blue cell tumors can metastasize to the thyroid gland, and clinical presentation, morphology, immunohistochemistry and molecular studies are helpful in differentiating between them.

Absence or Presence of High-Grade Squamous Intraepithelial Lesion in Cervical Conization Specimens: A Clinicopathologic Study of 540 Cases.

OBJECTIVES To explore the implications of cervical conization specimens lacking the targeted high-grade squamous intraepithelial lesions (negative cone). METHODS We studied 540 conization procedures: 400 positive cones and 140 negative cones. Clinicopathologic features and 2-year follow-up results were reported. RESULTS Negative cones comprised 22% of procedures triggered by CIN2 or higher biopsies. Procedures triggered by cytology produced much higher percentages of negative cones (37% high-grade squamous intraepithelial lesion [HSIL], 46% atypical squamous cells-cannot exclude high-grade squamous intraepithelial lesion [ASC-H], and 76% low-grade squamous intraepithelial lesion-cannot exclude high-grade squamous intraepithelial lesion [LSIL-H]). Upon reviewing negative excision-triggering biopsy and cytology, we downgraded 24 (24%) CIN2 biopsies, three (14%) HSIL, five (83%) ASC-H, and 12 (92%) LSIL-H. One-third of our negative cones can be attributed to overdiagnosis either on biopsy or cytology. Patients with negative cones were older and had smaller excisions, negative colposcopic findings, and negative/equivocal high-risk human papillomavirus (HR-HPV). Within 2 years, 35 (25%) women with negative cones experienced ASCUS or LSIL. Only one (0.7%) recurred as CIN3, a significantly lower percentage than women with positive cones (13%). CONCLUSIONS We advocate careful review of all excision-triggering biopsy and cytology, especially in cases of LSIL-H. Patients with negative cones should be surveyed with cytology and HR-HPV testing.

Phenotypic alterations in breast cancer associated with neoadjuvant chemotherapy: A comparison with baseline rates of change

Several studies have documented phenotypic alterations in breast cancer associated with neoadjuvant chemotherapy [NACT], but many of these studies are limited by the fact that they did not account for the baseline rate of expected phenotypic change between biopsies and resections in the absence of NACT. Herein, we assess whether the NACT-associated rate of phenotypic change is significantly different than would be expected in a control population of patients that did not receive NACT. From a pathologic database, we documented the estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER2/neu) phenotypes of consecutive invasive breast carcinomas (n=826), as well as the subset in which at least one of these tests was assessed in both the biopsy and resection (n=340). We then compared the rates of phenotypic change in the patients that did (n=65) and did not (n=275) receive NACT. Respectively, 49.2% and 36% of the NACT and non-NACT groups showed a biopsy-to-resection change in status for at least one biomarker (p=0.0005). The NACT and non-NACT groups showed the following respective rates of a biopsy-to-resection change in phenotype: ER (9.2% vs 2.5%, p=0.02); PR (30.7% vs 8%, p=0.000006); Her2/neu-IHC (25% vs 22.3%, p=0.7), Her2/neu-FISH (7% vs 3%, p=0.6). The direction of change in the NACT group was positive in the biopsy to negative in the resection in >70% of cases for all markers. For ER and PR, there was no statistically significant difference between cases that showed a biopsy-to-excision change in phenotype and those that were more phenotypically stable regarding a wide array of clinicopathologic variables. The average percentage of ER/PR-immunoreactive tumor cells in the pre-NACT biopsies was significantly lower in the phenotypically altered cases as compared to the phenotypically stable cases. Our findings confirm that phenotypic alterations in breast cancer occur after NACT, and that these changes are more pronounced for hormone receptors (especially PR); Significant NACT-associated alterations were not apparent for HER2/neu. A distinct pathologic profile for cases displaying a phenotypic change within the NACT group was not demonstrable. The pre-NACT levels of ER and PR may affect the likelihood of a phenotypic change. These results highlight the need for repeat testing in residual tumors after NACT.

Does a p53 Wild-type Immunophenotype Exclude a Diagnosis of Endometrial Serous Carcinoma?

An aberrant p53 immunophenotype may be identified in several histotypes of endometrial carcinoma, and is accordingly recognized to lack diagnostic specificity in and of itself. However, based on the high frequency with which p53 aberrations have historically been identified in endometrial serous carcinoma, a mutation-type immunophenotype is considered to be highly sensitive for the histotype. Using an illustrative case study and a review of the literature, we explore a relatively routine diagnostic question: whether the negative predictive value of a wild-type p53 immunophenotype for serous carcinoma is absolute, that is, whether a p53-wild type immunophenotype is absolutely incompatible with a diagnosis of serous carcinoma. The case is an advanced stage endometrial carcinoma that was reproducibly classified by pathologists from 3 institutions as serous carcinoma based on its morphologic features. By immunohistochemistry, the tumor was p53-wild type (DO-7 clone), diffusely positive for p16 (block positivity), and showed retained expression of PTEN, MSH2, MSH6, MLH1, and PMS2. Next generation sequencing showed that there indeed was an underlying mutation in TP53 (D393fs*78, R213*). The tumor was microsatellite stable, had a low mutational burden (4 mutations per MB), and displayed no mutations in the exonuclease domain of DNA polymerase epsilon (POLE) gene. Other genomic alterations included RB1 mutation (R46fs*19), amplifications in MYST3 and CRKL, and ARID1A deletion (splice site 5125-94_5138del108). A review of the recent literature identified 5 studies in which a total of 259 cases of serous carcinoma were whole-exome sequenced. The average TP53 mutational rate in endometrial serous carcinoma was only 75% (range, 60 to 88). A total of 12 (33%) of 36 immunohistochemical studies reported a p53-aberrant rate of <80% in endometrial serous carcinoma. We discuss in detail several potential explanations that may underlie the scenario of serous carcinoma-like morphology combined with p53-wild-type immunophenotype, including analytic limitations, a nonserous histotype displaying morphologic mimicry of serous carcinoma, and true biological phenomena (including the possibility of a TP53-independent pathway of endometrial serous carcinogenesis). Ultimately, our central thematic question is provisionally answered in the negative. At present, the available data would not support a categorical conclusion that a p53 alteration is a necessary and obligate component in the genesis and/or diagnosis of endometrial serous carcinoma. On the basis of their collective experience, the authors proffer some recommendations on the use of p53 immunohistochemistry in the histotyping of endometrial carcinomas.

Familial Breast Cancer and Genetic Predisposition in Breast Cancer

Approximately 10 % of breast cancer patients are carriers of gene mutations susceptible for the development of breast cancer. BRCA1, BRCA2, and TP53 genes are associated with a high risk of developing breast cancer in carriers and hence are referred to as high-penetrance genes. ATM (Ataxia Telangiectasia Mutated Gene), CHEK2, BRIP1, PALB2, RAD50, PTEN, CDH1, STK11, etc. are examples of moderate penetrance genes, while single nucleotide polymorphisms (SNPs) are considered low penetrance.