Kelly T. Huynh

Epigenetic Biomarkers in Skin Cancer

Epigenetic aberrations have been associated with cutaneous melanoma tumorigenesis and progression including dysregulated DNA gene promoter region methylation, histone modification, and microRNA. Several of these major epigenetic aberrations have been developed into biomarkers. Epigenetic biomarkers can be detected in tissue and in blood as circulating DNA in melanoma patients. There is strong evidence that biomarkers in cutaneous melanoma will have an important role as companions to therapeutics and overall patient management. Important progress has been made in epigenetic melanoma biomarker development and verification of clinical utility, and this review discusses some of the key current developments and existing challenges.

Comparison of Outcomes of Breast Conserving Therapy in Multifocal and Unifocal Invasive Breast Cancer

BACKGROUND There is controversy about whether breast conserving therapy (BCT) should be contraindicated in multifocal (MF) breast cancer. Few studies have reported on the oncologic safety of BCT in MF breast cancer. STUDY DESIGN We reviewed a prospective database of 1,169 women with invasive breast cancer who were treated with segmentectomy and whole breast irradiation from 1991 through 2009 and followed at our institution. Multifocal breast cancer was defined as 2 or more distinct tumors excised with a single incision or segmentectomy. We compared 2 groups, MF and unifocal breast cancer patients, with respect to demographics, tumor characteristics, adjuvant systemic therapy, local recurrence (LR), disease-free survival (DFS), and overall survival (OS). RESULTS One hundred sixty-four patients with MF and 999 with unifocal invasive breast cancer were treated with BCT. Median follow-up was 112 months. Compared with the unifocal group, patients in the MF group had higher 10-year LR (0.6% vs 6.1%, p < 0.001) and lower 10-year DFS (97.7% vs 89.3%, p < 0.001) and OS (98.4% vs 85.8%, p < 0.001). On multivariable analysis, multifocality was independently significantly associated with local recurrence-free survival (LRFS), DFS, and OS. CONCLUSIONS Our data suggest that BCT in MF breast cancer is oncologically safe but may result in a slightly inferior outcome compared with BCT in unifocal breast cancer.

Brain metastasis is predetermined in early stages of cutaneous melanoma by CD44v6 expression through epigenetic regulation of the spliceosome

Melanoma brain metastasis (MBM) is frequent and has a very poor prognosis with no current predictive factors or therapeutic molecular targets. Our study unravels the molecular alterations of cell‐surface glycoprotein CD44 variants during melanoma progression to MBM. High expression of CD44 splicing variant 6 (CD44v6) in primary melanoma (PRM) and regional lymph node metastases from AJCC Stage IIIC patients significantly predicts MBM development. The expression of CD44v6 also enhances the migration of MBM cells by hyaluronic acid and hepatocyte growth factor exposure. Additionally, CD44v6‐positive MBM migration is reduced by blocking with a CD44v6‐specific monoclonal antibody or knocking down CD44v6 by siRNA. ESRP1 and ESRP2 splicing factors correlate with CD44v6 expression in PRM, and ESRP1 knockdown significantly decreases CD44v6 expression. However, an epigenetic silencing of ESRP1 is observed in metastatic melanoma, specifically in MBM. In advanced melanomas, CD44v6 expression correlates with PTBP1 and U2AF2 splicing factors, and PTBP1 knockdown significantly decreases CD44v6 expression. Overall, these findings open a new avenue for understanding the high affinity of melanoma to progress to MBM, suggesting CD44v6 as a potential MBM‐specific factor with theranostic utility for stratifying patients.

Epigenetics of estrogen receptor-negative primary breast cancer

Increasingly, breast cancer is being recognized as a heterogeneous disease comprised of molecularly and phenotypically distinct intrinsic tumor subtypes with different clinical outcomes. This biological heterogeneity has significant implications, particularly as it relates to expression profiling of estrogen receptor (ER) status, as classifying breast cancers based on hormone receptor expression impacts not only prognosis but also treatment options and long-term outcomes. Epigenetics has emerged as a promising field for the assessment of hormone receptor status. Epigenetic aberrations have been shown to regulate ER and offer reversible targets for development of new therapies. This review covers ER-negative breast tumor epigenetic aberrations and summarizes the major epigenetic mechanisms governing ER expression and how it impacts treatment of ER-negative breast cancer.

Epigenetics of regional lymph node metastasis in solid tumors

Regional nodal status remains one of the most important prognostic factors in several solid tumors including melanoma, breast cancer, and gastrointestinal malignancies. However, despite the accuracy of lymph node (LN) staging, patients who are LN negative are still at risk for development of recurrence and distant metastasis. As such, numerous molecular studies have focused on genetic and transcriptome changes in primary and metastatic tumors to discover molecular determinants that can predict aggressive metastatic disease and/or correlated to clinical outcomes. More recently, epigenetic aberrations have been investigated in solid cancers and are associated with tumorigenesis and disease progression. These epigenetic alterations have demonstrated potential utility as diagnostic and prognostic biomarkers and are being developed into novel targeted treatment strategies, as epigenetic changes can be reversed by appropriate drugs. If patients who are at increased risk of developing metastases or recurrence can be accurately identified, this will help stratify patients into more appropriate treatment and follow-up. This review discusses some of the recent studies on regional LN metastases in melanoma, breast cancer, and colorectal cancer, focusing on the potential clinicopathological utility of epigenetic aberrations in the management of cancer patients.

Sentinel lymph node biopsy and nodal ultrastaging in colorectal cancer.

AbstractThe tumor status of the regional lymph nodes is the most important prognostic indicator in colorectal cancer (CRC), as it is in other solid tumors. Sentinel lymph node biopsy (SLNB), which has profoundly impacted the treatment of melanoma and breast cancer, has been applied in CRC in an attempt to improve nodal staging accuracy. The challenge lies in identifying patients who have tumor-negative nodes but are at high risk of regional or distant failure and therefore may benefit from adjuvant chemotherapy. Because standard pathological analysis of lymph nodes may incorrectly stage colon cancer, multiple studies have investigated nodal ultrastaging based on identification and immunohistochemical and/or molecular assessment of the sentinel node. This review focuses on the technique of SNLB, its feasibility and validity, and the controversies that remain regarding the clinical significance of nodal ultrastaging in CRC.

Multiplex Gene Profiling of Cell-Free DNA in Patients With Metastatic Melanoma for Monitoring Disease

Purpose Hotspot blood cell-free DNA (cfDNA) biomarker assays have limited utility in profiling tumor heterogeneity and burden and in capturing regional metastasis with low disease burden in patients with melanoma. We investigated the utility of a sensitive 54-cancer gene digital next-generation sequencing approach targeting blood cfDNA single nucleotide variants (SNVs) and copy number amplification for monitoring disease in patients with melanoma with regional or distant organ metastasis (DOM). Patients and Methods A total of 142 blood samples were evaluated by digital next-generation sequencing across two patient cohorts. Cohort 1 contained 44 patients with stage II, III, or IV disease with matched tumor DNA at the time of surgery or DOM. Cohort 2 consisted of 12 overlapping patients who were longitudinally monitored after complete lymph node dissection to DOM. Results In cohort 1, cfDNA SNVs were detected in 75% of patients. Tumor-cfDNA somatic SNV concordance was 85% at a variant allele fraction of ≥ 0.5%. An SNV load (number of unique SNVs detected) of greater than two SNVs and an SNV burden (total cumulative SNV VAF) of > 0.5% were significantly associated with worse overall survival (P < .05) in stage IV patients. In cohort 2, 98 longitudinal blood samples along with matched regional and distant metastases from 12 stage III patients were analyzed before complete lymph node dissection and throughout disease progression. cfDNA SNV levels correlated with tumor burden (P = .019), enabled earlier detection of recurrence compared with radiologic imaging (P < .01), captured tumor heterogeneity, and identified increasing SNVs levels before recurrence. Conclusion This study demonstrates significant utility for cfDNA profiling in patients with melanoma with regional and/or distant metastasis for earlier detection of recurrence and progression and in capturing tumor evolution and heterogeneity, thus impacting how patients with melanoma are monitored.

Papillary lesions of the breast: Can larger core needle biopsy samples identify patients who may avoid surgical excision?

44 Background: Papillary lesions of the breast are frequently diagnosed on core needle biopsy (CNB). The ability to distinguish benign from atypical/malignant papillary lesions is limited by the representative nature of the biopsy method; thus follow-up excision is usually recommended. We aimed to determine if larger CNB samples can more reliably predict the true benign nature of a papillary lesion, thereby sparing certain patients a formal surgical excision. METHODS We reviewed medical records of 53 female patients diagnosed with histologically benign papillary lesions on CNB from 2000 to 2010, who subsequently underwent surgical excision. Pathology slides of the CNB were reviewed to document the benign histologic features of the papilloma, the number of cores sampled and the area of tissue biopsied (mm2). Statistical analysis was performed to identify the characteristics of the CNB that were associated with retention of benign histology on excision. RESULTS Atypical ductal hyperplasia (ADH) and carcinoma were identified in 6% (3/53) and 8% (4/53) of papillary lesions, respectively, when excised. Clinical and radiographic characteristics did not distinguish the ADH/malignant lesions from benign papillomas. The CNB needle sizes ranged from 9- to 18-gauge (median 14). The number of cores sampled ranged from 3-16 (mean 4.5). Patients with benign excisions had a significantly larger area of tissue sampled by CNB than those found to have ADH/malignant lesions on excision (mean ± SD: 95.6 ± 101.2 vs. 41.7 ± 21.9, respectively, p=0.003). By logistic regression, CNB tissue samples consisting of ≥7 cores, or measuring >96 mm2 in aggregate, had a negative predictive value for ADH/malignancy of 100% (AUC of 0.69 and 0.68, respectively). CONCLUSIONS Although no clinical or radiologic features distinguished benign from pathologically significant papillary lesions, larger sample sizes significantly improved the predictive value of benign histology on CNB. A papilloma sampled by ≥ 7 cores or > 96 mm2 showing benign histology at CNB, retained benign features upon excision. Close surveillance may be a reasonable option for patients whose benign papillomas are generously sampled at the time of CNB.