BMC Cancer. 2009 Nov 20;9:404.

The effect of low-level laser irradiation (In-Ga-Al-AsP – 660 nm) on melanoma in vitro and in vivo.

Frigo L, Luppi JS, Favero GM, Maria DA, Penna SC, Bjordal JM, Bensadoun RJ, Lopes-Martins RA.

Laboratory of Pharmacology and Phototherapy of Inflammation, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo – São Paulo 05508-900 SP – Brasil.

BACKGROUND: It has been speculated that the biostimulatory effect of Low Level Laser Therapy could cause undesirable enhancement of tumor growth in neoplastic diseases. The aim of the present study is to analyze the behavior of melanoma cells (B16F10) in vitro and the in vivo development of melanoma in mice after laser irradiation. METHODS: We performed a controlled in vitro study on B16F10 melanoma cells to investigate cell viability and cell cycle changes by the Tripan Blue, MTT and cell quest histogram tests at 24, 48 and 72 h post irradiation. The in vivo mouse model (male Balb C, n = 21) of melanoma was used to analyze tumor volume and histological characteristics. Laser irradiation was performed three times (once a day for three consecutive days) with a 660 nm 50 mW CW laser, beam spot size 2 mm(2), irradiance 2.5 W/cm(2) and irradiation times of 60s (dose 150 J/cm(2)) and 420s (dose 1050 J/cm(2)) respectively. RESULTS: There were no statistically significant differences between the in vitro groups, except for an increase in the hypodiploid melanoma cells (8.48 +/- 1.40% and 4.26 +/- 0.60%) at 72 h post-irradiation. This cancer-protective effect was not reproduced in the in vivo experiment where outcome measures for the 150 J/cm(2) dose group were not significantly different from controls. For the 1050 J/cm(2) dose group, there were significant increases in tumor volume, blood vessels and cell abnormalities compared to the other groups. CONCLUSION: LLLT Irradiation should be avoided over melanomas as the combination of high irradiance (2.5 W/cm(2)) and high dose (1050 J/cm(2)) significantly increases melanoma tumor growth in vivo.

Eur J Dermatol. 2010 May-Jun;20(3):334-8. Epub 2010 Apr 27.

Melanoma after laser therapy of pigmented lesions–circumstances and outcome.


Zipser MC, Mangana J, Oberholzer PA, French LE, Dummer R.

Department of Dermatology, University Hospital of Zurich, Gloriastrasse 31, 8091 Zurich, Switzerland.


The use of laser therapy in the treatment of pigmented lesions is a controversial issue as it can delay melanoma diagnosis and may negatively impact mortality. Few cases of melanoma after laser therapy have been reported. It is still unknown whether melanoma can be induced by lasers. We discuss the outcomes of twelve patients presenting with melanoma subsequent to previous treatment with laser. In four patients, a skin biopsy was performed before laser treatment. Histology was re-evaluated by a panel of experienced dermatopathologists and analyzed in the context of clinical and photo-optical data. There was evidence for pathological misdiagnosis in two cases. The other two cases initially presented with non-suspicious features before laser treatment and were clearly diagnosed as melanoma thereafter, opening the possibility of melanoma induction by laser treatment. Most patients were female and presented with facial lesions. Three patients have already died of melanoma and two are in stage IV, showing progressive disease with distant metastases. Laser therapy is a common treatment for pigmented lesions, increasing the risk of delayed melanoma diagnosis. This prevents appropriate and timely therapy, and may therefore lead to a fatal outcome. A careful examination of all pigmented lesions using surface microscopy and representative biopsies in combination with a close follow-up is recommended.

J Dtsch Dermatol Ges. 2008 May;6(5):386-8. Epub 2007 Nov 26.

Never perform laser treatment of skin tumors with clinical “EFG” criteria.

Never perform laser treatment of skin tumors with clinical “EFG” criteria.


[Article in English, German]

Giacomel J, Zalaudek I, Mordente I, Nicolino R, Argenziano G.

Mends St. Medical Centre, South Perth, Western Australia, Australia.


Laser treatment is a common procedure for the treatment of cosmetically troubling skin lesions but has the limitation that histopathologic diagnosis is usually not obtained prior to treatment. Laser treatment of melanomas with benign clinical features may delay or make more difficult the correct diagnosis of such tumors. A helpful tool to identify clinically innocent appearing melanomas is the “EFG” rule, summarizing the common clinical features as “elevated, firm skin lesions showing continuous growth”. We report a 42-year-old woman who presented with a recurrent and metastatic melanoma after laser treatment of a tumor which was apparently clinically innocent and highlight the clinical features of such benign-looking melanomas.

J Dtsch Dermatol Ges. 2003 Jan;1(1):47-50.

Pseudomelanoma following laser treatment or laser-treated melanoma?


[Article in German]

Böer A, Wolter M, Kaufmann R.

Zentrum der Dermatologie und Venerologie, Klinikum der J. W. Goethe-Universität, Frankfurt am Main.


BACKGROUND: The increasing use of lasers for the removal of pigmented skin lesions has led to a growing risk of erroneously treated malignant melanocytic tumours. PATIENTS AND METHODS: In two patients, both of whom developed a melanoma, the lesions were initially misdiagnosed clinically as a benign naevus and treated with laser vaporisation. RESULTS: On recurrence of the tumours, the diagnosis of melanoma was finally established by histological examination of the excised tumours in which differentiation from pseudomelanoma remained difficult. CONCLUSIONS: In such cases of initially misdiagnosed melanomas, laser removal not only complicates and delays the correct diagnosis but might also worsen the prognosis after recurrence of an incompletely removed tumour.

Int J Mol Med. 2002 Dec;10(6):701-5.

Inhibition of lung metastasis of B16 melanoma cells exposed to blue light in mice.

Ohara M, Kawashima Y, Kitajima S, Mitsuoka C, Watanabe H.

Otsuka Pharmaceutical Factory, Inc., Muya-cho, Naruto, Tokushima 772-8601, Japan.


The effects of blue light on B16 melanoma cells and on the metastasis of these cells to the lungs were investigated in mice. The exposure of B16 melanoma cells to blue light in two 20-min sessions resulted in marked suppression of cell growth measured at 7 days after exposure. When these cells were harvested, re-inoculated into medium and incubated for a further 7 days, their growth activity returned to almost the same level as that of cultured cells from the non-exposure control group. The melanoma cells harvested after 7 days of incubation were injected intravenously into mice. In the non-exposure group, black nodules developed on the lung surface and the nodules increased in size over time. In the blue-light-exposure group, the development of such black nodules on the lung surface was delayed, and the nodules were smaller. Histopathological examination revealed that blue light suppressed the growth of metastatic tumor cells, and no increase in the number of melanin-containing cells or atypical cells was induced in the metastatic lesions. These results suggest that blue light suppresses the metastasis of B16 melanoma cells.