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Prof. Martin O. Bergo[/caption]
MedicalResearch.com Interview with:
Prof. Martin O. Bergo
Sahlgrenska Cancer Center
Department of Molecular and Clinical Medicine
Institute of Medicine
University of Gothenburg
Gothenburg, Sweden
Medical Research: What is the background for this study? What are the main findings?
Prof. Bergo: Dietary antioxidants and antioxidant supplements can protect cells and people from harmful effects of free radicals. The free radicals have the potential, over time, to cause cancer. But why is this research field so enormously fraught with controversy, and why have clinical trials with antioxidants not established this potential anti-cancer effects? We believe it is because the question of “whether antioxidants protect against cancer” should be divided into two separate questions:
1. Do antioxidants protect a healthy cell or a tumor-free person from cancer in the future.?and
2. What is the impact of antioxidant supplementation on an already established tumor?
Focusing specifically on the second question, we showed previously that the antioxidants N-acetylcysteine and vitamin E markedly increase lung cancer progression in mice and cause human lung cancer cells to proliferate faster. The mechanism for this effect was directly linked to the ability of the antioxidants to scavenge free-radicals, which is why it is likely that other antioxidants, synthetic or natural, could have a similar effect. In the current study, we argued that it would be important to test this in malignant melanoma for three reasons.
First, melanoma cancer cells are known to be sensitive to changes in free radicals. Second, melanoma is the cancer that increases most in incidence and lethality in the western world.
And third, primary melanomas may be exposed to antioxidants from both the diet and from skin lotions and sun creams.
We found that supplementing the diet of mice with acetylcysteine has no impact on the primary tumors on the skin but doubles the rate of metastasis – i.e. the ability of the tumor cells to spread in the body. We found similar results with human malignant melanoma cells in culture:
antioxidants (acetylcysteine and vitamin E) increased their ability to migrate and invade surrounding tissue. Thus, all in all, we have found that antioxidants can worsen cancer in two different ways, one in the lung, and another in the skin.
Dr. Thomas Kirchhoff[/caption]
MedicalResearch.com Interview with:
Tomas Kirchhoff, PhD
Assistant Professor, Departments of Population Health and Environmental Medicine
NYU Langone Medical Center
Member, Laura and Isaac Perlmutter Cancer Center
NYU Langone
Medical Research: What is the background for this study?
Dr. Kirchhoff: Melanoma is the deadliest form of skin cancer, and the cause of approximately 80% of all skin cancer patients annually. One factor that can help reverse this negative trend is efficient prediction of which patients at early melanoma stage will likely progress to more advanced metastatic disease. Current clinical predictors of patient survival, based on tumor characteristics, are important, but are relatively non-specific to inform melanoma prognosis to an individual patient level. It is critical to identify other factors that can serve as more personalized markers of predicting the course of melanoma.
Medical Research: What are the main findings?
Dr. Kirchhoff: In our study, we found that inherited genetic markers that impact activity of certain immune genes correlate with melanoma survival. More specifically, our findings show that patients with more frequent forms of these genetic markers (genotypes) have, on average, a five-year shorter survival than patients with less common genotypes. We suggest that these genetic markers are independent of the current tumor surrogates and, as such, can serve as novel personalized markers of melanoma prognosis.
Dr. Jennifer Stein[/caption]
Pritesh Karia[/caption]
MedicalResearch.com Interview with:
Tanning Bed CDC Image[/caption]
MedicalResearch.com Interview with:
Myra Sendelweck M.Eng
M.D. Candidate 2018 and
Robert Dellavalle, MD, PhD, MSPH
Chief, Dermatology Service Denver VA Medical Center Denver, CO
University of Colorado School of Medicine
MedicalResearch: What is the background for this study? What are the main findings?
Response: Indoor tanning has increasingly been recognized amongst providers as a public health concern. Recent literature suggests an association between indoor tanning and other risky health behaviors in adolescents.
We were intrigued by this association. We analyzed a survey of Colorado high school students and found that those who tanned were also more likely to use various substances, such as steroids, alcohol, marijuana, and illicit drugs. Tanners were over five times as likely to report steroid use!
Dr. Jason Lee[/caption]
MedicalResearch.com Interview with:
Jason B. Lee MD
Professor , Clinical Vice Chair
Department of Dermatology and Cutaneous Biology
Director, Jefferson Dermatopathology Center
Thomas Jefferson University
Philadelphia, Pennsylvania
Medical Research: What is the background for this study? What are the main findings?
Dr. Lee: When initially described, Clark et al. suggested that dysplastic nevi were intermediate lesions that lie biologically on a spectrum between benign and malignant. As such, they were to be histologically graded as mild, moderate, and severe (or a combination thereof), with mild presumably closer to benign and severe closer to malignant. In this paradigm, adopted by most dermatologists, these nevi are routinely excised based on histologic grading and margin status. Recent outcomes of follow-up and excision studies of dysplastic nevi suggest that they are over treated as there have been very low rates of melanoma on re-excision.
An alternative approach considers dysplastic or eponymously Clark nevi as common acquired nevi, typically in fair skin individuals, and rejects the entire notion that they are intermediate lesions as there exists no formal proof of their intermediate status. This approach omits grading and margin status entirely, providing the clinician an explicit recommendation for excision only for those cases of diagnostic uncertainty. In this study, excision recommendation rate of dysplastic/Clark nevi was determined along with analysis of excision outcomes in a laboratory where non-grading histologic diagnostic approach to these nevi has been adopted.
The excision recommendation rate, representing the diagnostic uncertainty rate, was 11.1%. Out of 80% of the cases returned for excision, only 2.0% of the cases were interpreted as melanoma on excision; all were in situ or thin melanomas. This excision rate is much lower than in prior reports, which vary from 22-52%, while still capturing melanomas within this subset of lesions.
Dr. Susana Puig[/caption]
MedicalResearch.com Interview with:
Susana Puig MD PhD
Chief Dermatology Service
Research Director
"Melanoma: Imaging, genetics and immunology" at IDIBAPS
Consultant & Assistant Professor
Melanoma Unit, Dermatology Department
Hospital Clinic, University of Barcelona
Barcelona Spain
Medical Research: What is the background for this study? What are the main findings?
Dr. Puig: CDKN2A is the main high-penetrance melanoma susceptibility gene. A rare functional variant in MITF, p.E318K (rs149617956), has been identified as a moderate risk allele in melanoma susceptibility and also predisposes to renal cell carcinoma.
In this study MITF p.E318K was associated with an increased melanoma risk (OR=3.3, p<0.01), especially in patients with multiple primary melanoma (OR=4.5, p<0.01) and high nevi count (>200 nevi) (OR=8.4, p<0.01). Interestingly, two fast growing melanomas were detected among two MITF p.E318K carriers during dermatologic digital follow-up. Furthermore, we have detected a similar prevalence of MITF p.E318K in CDKN2A wild-type and mutated individuals.
Dr. Bastian[/caption]
MedicalResearch.com Interview with:
Boris C. Bastian, MD, PhD
Professor of Dermatology and Pathology
Gerson and Barbara Bass Bakar Distinguished Professor in Cancer Research
University of California, San Francisco
Medical Research: What is the background for this study? What are the main findings?
Dr. Bastian: The cost of DNA sequencing has dropped substantially since the initial sequencing of the human genome in 2001. As a result, the most common cancer subtypes have now been sequenced, revealing the pathogenic mutations that drive them. A typical cancer is driven by 5-10 mutations, but we still do not understand the order in which these mutations occur for most cancers.
Determining the order in which mutations occur is challenging for cancers that are detected at a late stage. Melanomas, however, lend themselves to this type of analysis because they are pigmented and found on the surface of the skin, allowing them to be identified early. Sometimes, melanomas are even found adjacent to their remnant precursor neoplasms, such as benign nevi (also known as common moles). We performed detailed genetic analyses of 37 cases of melanomas that were adjacent to their intact precursor neoplasms. We microdissected and sequenced the surrounding uninvolved normal tissue, the precursor neoplasm, and the descendent neoplasm. By comparing the genetic abnormalities in each of the microdissected areas, we were able to decipher the order of genetic alterations for each case.
Our work reveals the stereotypic pattern of mutations as they occur in melanoma. Mutations in the MAPK pathway, usually affecting BRAF or NRAS, occur earliest, followed by TERT promoter mutations, then CDKN2Aalterations, and finally TP53 and PTEN alterations. Benign nevi typically harbor a single pathogenic alteration, whereas fully evolved melanomas harbor three or more pathogenic alterations. We also identified an intermediate stage of neoplasia with some but not all of the pathogenic mutations required for fully evolved melanoma. There has been a longstanding debate whether morphologically intermediate lesions, such as dysplastic nevi, truly constitute biological intermediates or whether they simply represent a gray zone of histopathological assessment. Our data indicates that these neoplasms are genuine biological entities. Finally, we observe evidence of UV-radiation-induced DNA damage at all stages of pathogenesis, implicating UV radiation in both the initiation and progression of melanoma.
