Human Basal Cell Carcinoma Research Articles

Expression of Basigin in human fetal, infantile and adult skin and in basal cell carcinoma.

Basigin is a glycosylated transmembrane protein belonging to the immunoglobulin superfamily and is thought to be associated with cell development and differentiation. We investigated the relation between Basigin expression and epidermal development in this study. Basigin expression was immunohistochemically investigated during organogenesis of human skin and in human basal cell carcinoma (BCC). Human fetal skin showed negative staining at 10 weeks of gestation. At 20 weeks, the cytoplasm and membranes of adnexal germ and hair follicular cells were strongly positive, while epidermal basal cells showed weakly positive staining. After birth, basal cells, suprabasal cells, anagen hair follicular cells and eccrine glandular cells showed positive staining. Membranes of basal cells expressed more Basigin compared to other cell components. Basigin was not detectable in granular cells and telogen hair follicular cells. Sixteen of 30 BCCs were entirely negative for Basigin. However, cells at budding areas of tumor masses were positive in 14 of the 30 BCCs. These findings suggest that 1) Basigin is associated with epidermal proliferation and differentiation, 2) most parts of BCCs might be derived from early fetal epidermal basal cells, and 3) that a part, only the budding area of BCCs, has the characteristics of epithelial germ cells.

Photodynamic therapy and diagnostic measurements of basal cell carcinomas using esterified and non-esterified δ-aminolevulinic acid

Various optical techniques were used to investigate relevant parameters involved in photodynamic therapy (PDT) of human basal cell carcinomas (BCCs). The aim of the study was to compare the diagnostic and therapeutic outcome when using topically applied methyl-esterified δ-aminolevulinic acid (ALA-ME) and δ-aminolevulinic acid (ALA). A total of 35 pathologically verified BCCs in 14 patients were investigated. A diode laser, emitting continuous light at 633 nm, was used to induce PDT. The diagnostic measurements were performed before, during, and after PDT. Laser-induced fluorescence (LIF) was used to monitor the build-up of the ALA/ALA-ME-induced protoporphyrin IX ( PpIX ). The superficial tissue perfusion was measured with laser-Doppler perfusion imaging (LDPI) and the temperature of the lesion and the surrounding tissue was imaged with an IR-camera. A clear demarcation between the lesion and the normal skin was detected with LIF before the treatment for both PpIX precursors. The fluorescence measurements suggest that PpIX builds up to a higher degree and more selectively in the tumour following ALA-ME as compared to ALA. The LDPI measurements indicate a local transient restriction in blood perfusion immediately post-PDT. The measurement with the IR-camera revealed a temperature rise of about 1–2 °C during the treatment.

Overexpression of interleukin-6 in human basal cell carcinoma cell lines increases anti-apoptotic activity and tumorigenic potency

Interleukin-6 (IL-6) is a pleiotropic cytokine that is capable of modulating the diverse functions of cells such as acute phase responses and inflammation. Excessive or insufficient production of IL-6 may contribute to certain diseases of the skin. The aim of this study was to investigate the possible role of IL-6 in the tumorigenesis of basal cell carcinoma (BCC). Initially, we transfected IL-6 expression vector, under the control of a CMV promoter, into human BCC cells and successfully obtained IL-6-overexpressing clones (BCC/IL-6-c1 and BCC/IL-6-c2) and a mixture (BCC/IL-6). DNA synthesis assay determined using (3)H-thymidine pulse incorporation revealed that IL-6-expressing BCC cells exhibited a much higher DNA synthesis rate than the neo control or parental BCC cells. We also detected a greater abundance of IL-6-expressing cell colonies formed in soft agar than in the vector control cells. Furthermore, BCC/IL-6 cells, but not vector control cells, were resistant to UV and photodynamic therapy (PDT)-induced apoptosis, as confirmed using DNA fragmentation and morphologic change analyses. Immunoblot analysis showed that Mcl-1, an anti-apoptotic protein, was specifically up-regulated IL-6 transfectants but not in the control cells. Transient transfection of IL-6 transfectants with antisense mcl-1 greatly enhanced their apoptosis frequency by UV treatment. In tumorigenesis assay, IL-6 transfected clones formed tumors in nude mice more rapidly than the control cells. These tumors appeared to be highly vascularized using pathological examination. Supportive of this finding, we found that IL-6 transfected cells expressed elevated levels of two angiogenic factors, cyclooxygenase (Cox)-2 and vascular endothelial growth factor (VEGF). These results suggest that overexpression of IL-6 enhances the tumorigenic activity of BCC cells by both suppressing apoptosis and actively promoting angiogenesis.

Mutations of the PH Domain of Protein Kinase B (PKB/AKT) Are Absentin Human Epidermal Skin Tumors

Background: While for most human solid tumors genetic alterations of few distinct genetic regions have been found, studies on basal cell carcinomas (BCC) have shown the prevalence of several abnormalities including alterations of the three ras genes, GAP (GTPase activating protein), p53, PTCH (the human homologue of Drosophila patched) and SMOH (the human homologue of Drosophila smoothened). On the other hand, during the last decade, a new oncogene, protein kinase B (PKB/AKT), has been characterized and found to be overexpressed in certain human tumors. In vivo activation of PKB/AKT necessitates its recruitment to the cell membrane mediated by the N-terminal pleckstrin homology (PH) domain. Objective: We investigated whether mutations of this mandatory domain are present in a subset of human epidermal skin tumors. Methods: RNA of 19 human skin tumors including 13 BCC, 4 squamous cell carcinomas (SCC; including 1 keratoacanthoma) and 2 neurofibromas of different size and tumor stage were used for reverse transcription and subsequent PCR amplification of the PH domain of PKB/AKT. Results: Cycle sequencing of the purified PCR products did not reveal any mutation of the PH domain of PKB/AKT. Conclusion: In human BCC and SCC, mutations of the PH domain of PKT/AKT do not play a major role during the carcinogenesis of these tumors.

STAGE- AND TISSUE-SPECIFIC EXPRESSION OF A β-1,4-GALACTOSYLTRANSFERASE IN THE EMBRYONIC EPIDERMIS

Changes in oligosaccharide structures of glycoconjugates have been observed, and are postulated to have key roles in embryonic development and differentiation. N-Acetylglucosamine (GlcNAc) beta-1,4-galactosyltransferase (beta4GalT) AKI showed different expression patterns in time and space, and different enzymatic activity from the other known family members. The epidermis of mouse embryo included a high level of AKI activities, which transferred galactose (Gal) to endogenous glycoprotein (molecular weight 130 kDa) (GP130). The maximum activity was for 13.5-d postcoitum embryos. Specific antibody against AKI inhibited 81% of GlcNAc betaGalT activities, which indicates that AKI represents the major part of the embryonic epidermis enzymes. AKI shows 2.2 times higher galactosyltransferase activity toward Gal-acceptor glucose with alpha-lactalbumin (alpha-LA) than toward GlcNAc without alpha-LA. AKI is also expressed in mouse melanoma and leukemia cell lines and in human basal cell carcinoma specimens. The GP130 Gal acceptor once galactosylated by AKI may be directly involved in epidermal differentiation and oncogenesis.

Hedgehog signalling in cancer.

Hedgehog signalling is a key regulator of embryonic development controlling proliferation and/or cell fate determination. With identification of the Hedgehog receptor PTCH1 as a tumour suppressor gene that underlies the human nevoid basal cell carcinoma syndrome (NBCCS), the Hedgehog signalling pathway was firmly linked to cancer. It now appears that constitutive activation of Hedgehog signalling, by inactivating mutations in PTCH1 or activating mutations in the coreceptor SMOH, is required and possibly sufficient for basal cell carcinoma development and also contributes to the formation of a variety of other tumour types, including medulloblastoma and rhabdomyosarcoma. Several lines of evidence, including transgenic mice experiments, suggest that the critical cellular effect is stimulation of proliferation mediated by the transcriptional effector GLI1. Additional components of the signal transduction machinery as well as essential target genes remain to be identified, and involvement of the Hedgehog signalling pathway in other tumour types and/or hereditary cancer predisposition syndromes is to be expected.

High Frequency of Loss of Heterozygosity on Chromosome Region 9p21–p22 but Lack of p16INK4a/p19ARF Mutations in Greek Patients with Basal Cell Carcinoma of the Skin

Basal cell carcinoma of the skin is the most common neoplasia in humans. Previous studies have shown the existence of allelic imbalance (loss of heterozygosity and microsatellite instability) in BCC on several human chromosomes. Chromosome region 9p21-p22 harbors the CDKN2a/p16INK4a, p19ARF, and p15INK4b tumor suppressor genes. To determine the contribution of these genes to the development of basal cell carcinomas we looked for evidence of allelic imbalance in 67 sporadic basal cell carcinoma specimens from Greek patients and screened 28 of them presenting loss of heterozygosity at 9p21-p22 for germline mutations in p16INK4a and p19ARF genes. Chromosome regions 17q21 and 17p13 were also screened for allelic imbalance in all the 67 basal cell carcinoma specimens. Overall, 69% (46 of 67) of the specimens displayed loss of heterozygosity in at least one microsatellite marker, whereas only six of the 67 (9%) exhibited microsatellite instability. For the 9p21-p22 locus the overall frequency of loss of heterozygosity reached 55% (37 of 67) and is the highest reported. The overall frequency of loss of heterozygosity for the 17q21 locus is 34% (22 of 64) and for the 17p13 locus is 11% (seven of 65). Two of the 28 loss of heterozygosity positive cases were heterozygous for a previously described polymorphism, Ala148Thr, in exon 2 of the CDKN2a gene. This is the first demonstration of polymorphism in the CDKN2a gene in human basal cell carcinomas. No sequence variation in exon 1beta of the p19ARF gene was found. Our results provide evidence of a significantly high occurrence of loss of heterozygosity for the 9p21-p22 locus; however, lack of p16INK4a/p19ARF mutation suggests that these genes seem not to be implicated by mutational inactivation in the development of basal cell carcinoma. Other(s), yet unidentified, tumor suppressor gene(s) located in this locus may be related to this specific type of skin cancer.

High Dermal Mast Cell Prevalence is a Predisposing Factor for Basal Cell Carcinoma in Humans

Ultraviolet B radiation (280-320 nm) can initiate skin cancer as well as suppress the immune system, thereby preventing the rejection of ultraviolet-B-induced tumors. Recently we reported that there was not only a correlation but also a functional link between dermal mast cell prevalence and susceptibility to ultraviolet-B-induced systemic immunosuppression in multiple strains of mice. In this study, we investigated whether increased dermal mast cell prevalence is a significant predisposing factor for basal cell carcinoma development in humans. In 21 Danes with a history of basal cell carcinoma and 20 control subjects of similar age, sex, skin phototype, and recreational sun exposure over the past 12 mo, dermal mast cell prevalence was quantified on non-sun-exposed buttock skin. We investigated this skin site in order to avoid any changes in mast cell prevalence caused by sun exposure and assumed that the prevalence of mast cells in buttock skin correlated with that at sun-exposed sites at critical times in the development of basal cell carcinomas. Patients with a history of basal cell carcinoma had a significantly higher median dermal mast cell prevalence than control subjects (p = 0.01, Mann-Whitney U ). No correlation was observed between dermal mast cell prevalence and age of basal cell carcinoma patients and control subjects. These results suggest that increased dermal mast cell prevalence is a predisposing factor for basal cell carcinoma development in humans. We hypothesize that mast cells function in humans, as in mice, by initiating immunosuppression and thereby allowing a permissive environment for basal cell carcinoma development.

Expression of the pro-apoptotic caspase 3/CPP32 in cutaneous basal and squamous cell carcinomas.

Apoptosis, a process of programmed cell death, plays an important role in normal and pathologic tissue homeostasis. The apoptotic cascade is triggered by caspases, a family of cystein proteases, among which caspase 3 (CPP32) seems to be the most directly related to apoptosis. Until now, few, if any, data exist on the role of CPP32 in skin tumors. We studied by immunohistochemistry, Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR) the expression of CPP32 in specimens of normal human skin, basal and squamous cell carcinomas. CPP32 (both at the protein and mRNA level) was detected within epidermal and adnexal keratinocytes. CPP32 was also expressed in tumor masses of squamous cell carcinomas and more weakly in basal cell carcinomas; no correlation was found between CPP32 expression and depth of tumor invasion. CPP32 was occasionally expressed in tumor-infiltrating lymphocytes and peritumor endothelial cells. The expression of CPP32 in normal skin and in tumors arising from it suggests that this enzyme is involved in their homeostasis; its precise functional significance awaits further investigation.

Basal cell carcinomas in mice overexpressing Gli2 in skin.

Approximately 1,000,000 epithelial skin cancers are diagnosed in the United States each year and most are basal cell carcinomas (BCCs). The pathogenesis of these tumours involves constitutive activation of the Sonic hedgehog (Shh) signalling pathway (for review, see ref. 1). In many BCCs this can be attributed to loss-of-function mutations of PTCH (refs 2,3), which encodes a SHH receptor and antagonist. The specific downstream effector in the Shh pathway leading to cancer development is unknown. Here we show that transgenic mice overexpressing the transcription factor Gli2 in cutaneous keratinocytes develop multiple BCCs. These results establish Gli2 as a potent oncogene in skin and suggest a pivotal role for this transcription factor in the development of human BCC.

Immunohistochemical analysis of DNA mismatch repair enzyme hMSH-2 in normal human skin and basal cell carcinomas.

We have analysed the expression and distribution of the DNA mismatch repair enzyme hMSH-2 in normal skin and basal cell carcinomas. hMSH-2 protein was investigated immunohistochemically (normal human skin: n = 10; basal cell carcinomas: n = 16) on frozen sections using a highly sensitive streptavidin-peroxidase technique and a specific mouse monoclonal antibody (clone FE11). In normal human skin, we found nuclear immunoreactivity for hMSH-2 in epidermal keratinocytes of the basal and first 1-3 suprabasal cell layers. All basal cell carcinomas analysed revealed strong nuclear imunoreactivity that was pronounced in peripheral tumour cells and cells of the palisade. Expression of hMSH-2 protein was consistently and strongly upregulated in tumour cells of the carcinomas as compared to adjacent unaffected epidermis or epidermis of normal human skin. Twelve of the sixteen carcinomas analysed revealed no visual correlation in comparing the labelling patterns for hMSH-2 with the labelling pattern for the proliferation marker Ki-67. Our findings indicate that (a) hMSH-2 is expressed in human epidermal keratinocytes, predominantly in lower cell layers of the viable epidermis; (b) expression of hMSH-2 protein is strongly upregulated in basal cell carcinomas as compared to unaffected epidermis; (c) the level of hMSH-2 proteins in the carcinomas is not exclusively regulated by the proliferative activity of these tumour cells; (d) inactivating mutations of the hMSH-2 gene may in the carcinomas not be involved in the carcinogenesis or microsatellite instability secondary to replication errors; (e) expression of hMSH-2 may be of importance for the genetic stability of basal cell carcinomas in vivo.

Ultraviolet and ionizing radiation enhance the growth of BCCs and trichoblastomas in patched heterozygous knockout mice.

Basal cell carcinomas, the commonest human skin cancers, consistently have abnormalities of the hedgehog signaling pathway and often have PTCH gene mutations. We report here that Ptch+/- mice develop primordial follicular neoplasms resembling human trichoblastomas, and that exposure to ultraviolet radiation or ionizing radiation results in an increase in the number and size of these tumors and a shift in their histologic features so that they more closely resemble human basal cell carcinoma. The mouse basal cell carcinomas and trichoblastoma-like tumors resemble human basal cell carcinomas in their loss of normal hemidesmosomal components, presence of p53 mutations, frequent loss of the normal remaining Ptch allele, and activation of hedgehog target gene transcription. The Ptch mutant mice provide the first mouse model, to our knowledge, of ultraviolet and ionizing radiation-induced basal cell carcinoma-like tumors, and also demonstrate that Ptch inactivation and hedgehog target gene activation are essential for basal cell carcinoma tumorigenesis.

Ultraviolet radiation mutagenesis of hedgehog pathway genes in basal cell carcinomas.

The identification of mutations in Hedgehog (HH) pathway genes in some basal cell carcinomas (BCC) and the detection of HH pathway dysregulation in almost all BCC confirms the importance of this developmental regulatory pathway in human BCC tumorigenesis. Moreover, the occurrence of UVB signature mutations in key HH pathway genes in BCC provides the first genetic evidence that UV radiation (UVR) may be the principal mutagen involved in BCC tumorigenesis. We review herein current advances in the understanding of the role of the HH pathway in BCC tumorigenesis including transgenic and knock-out animal models of HH pathway dysregulation. Furthermore, we summarize abnormalities in other tumor suppressors and oncogenes including ras and p53 and evidence for interactions between these regulatory genes and the HH pathway.

Expression of sonic hedgehog signal transducers, patched and smoothened, in human basal cell carcinoma.

In basal cell nevus syndrome (BCNS) patients, mutations of a gene, patched (ptc), which encodes a putative signal transducer of sonic hedgehog protein (SHH), were found and are thought to be one of the major causes of BCNS. The SHH signaling pathway is an important developmental pathway, and ptc protein (PTC) is a suppressive component serving as a receptor for the secreted SHH. Another transmembrane protein, smoothened (SMO), forms a complex with PTC and regulates this signaling pathway. Recent transgenic studies have strengthened the importance of the SHH signaling system in the etiology of basal cell carcinoma (BCC). In this study, we examined the expression patterns of mRNA for ptc and smo in two different BCC subtypes and normal skin. We found that the expressions of ptc and smo mRNA were enhanced in the tumor nests of the nodular BCC, especially at the advancing portions, but were under the detectable level in the superficial BCC cases examined, indicating that ptc and smo mRNA expressions might be associated with BCC tumor progression and divide the BCC histologic types into two subtypes, superficial and nodular types. In addition, no obvious signals for ptc and smo mRNA were detected in the normal human epidermis, appendages, or seborrheic keratosis, indicating that the abnormal proliferation of follicular epithelial cells caused by ptc, smo and/or other genetic changes, which also cause ptc and smo overexpressions, might result in BCC tumor formation.

The hedgehog signalling pathway and its role in basal cell carcinoma.

The hedgehog signalling pathway plays a vital role in Drosophila embryonic patterning and development. Hedgehog is a secreted protein, unrelated to classical growth factors, which seems to form concentration gradients across those tissues involved in pattern formation. Cloning of vertebrate homologues of hedgehog and other genes has illustrated the remarkable conservation of function of this pathway throughout evolution. The human homologue of patched, a receptor for the hedgehog protein, was cloned as the gene responsible for naevoid basal cell carcinoma syndrome (NBCCS/'Gorlin Syndrome'), an autosomal dominant condition in which patients suffer from multiple basal cell carcinomas and a wide spectrum of developmental abnormalities. Its role as a tumour suppressor gene in both NBCCS and sporadic basal cell carcinoma led to the suggestion that mutation or inactivation of human patched may be an essential step in development of basal cell carcinomas and other skin tumours. This review describes our current understanding of hedgehog signalling in Drosophila and vertebrates and its relation to the development of human basal cell carcinoma and other skin tumours, together with a discussion of future avenues of research into this critical and intriguing pathway.

Simulations on the selectivity of 5-aminolaevulinic acid-induced fluorescence in vivo

The knowledge of the exact time course of a photosensitizer in tumour and surrounding host tissue is fundamental for effective photodynamic therapy (PDT) and fluorescence-based diagnosis. In this study the time course of porphyrin fluorescence following topical application of 5-aminolaevulinic acid (ALA) using different formulations, concentrations and incubation times has been measured in amelanotic melanomas (A-Mel-3) ( n = 54) grown in transparent dorsal skinfold chambers of Syrian golden hamsters and in human basal cell carcinomas (BCCs) ( n = 40) in vivo. To simulate the accumulation of ALA-induced protoporphyrin IX (Pp IX), a three-compartment model has been developed and rate constants have been determined. The kinetics of both the A-Mel-3 tumours and the BCCs show a significantly higher fluorescence intensity in tumour as compared to normal surrounding host tissue. Maximal fluorescence intensity in A-Mel-3 tumours as a percentage of the reference standard used occurs 150 min post incubation (p.i.) using a 1, 3 or 10% (vol.) ALA solution buffered to pH 7.4 and 1 h incubation time. After a 4 h incubation time maximal fluorescence intensity in tumour is measured shortly p.i. A concentration of 10% ALA does not increase the fluorescence intensity as compared to 3% ALA following 4 h incubation, but either 3 or 10% ALA yields a significantly higher fluorescence after 4 h incubation time as compared to 1 h. The fluorescence intensity following an 8 h incubation reaches its maximum directly p.i. for all concentrations and then decreases exponentially. The fluorescence intensity in the surrounding host tissue shows no statistically significant difference regarding concentration or incubation time. At least during the first hour p.i., the fluorescence intensity measured in the surrounding tissue is lower as compared to that in the tumour in all groups. 24 h after topical application hardly any fluorescence is detectable in tumour or surrounding host tissue in all experimental groups. Incubating human BCCs with a 20% ALA cream (water-in-oil emulsion) or a 20% ALA gel (containing 40% dimethyl sulfoxide) for approximately 2 h yields a similar fluorescence intensity directly after incubation for either cream or gel. However, while yielding a maximum 120 min p.i. with cream, the fluorescence intensity increases for a longer time (about 2–3 h p.i.) and up to higher values using the gel formulation. In surrounding normal skin, cream as well as gel formulation yields a similar fluorescence intensity directly after incubation. Afterwards the fluorescence intensity decreases slowly using the cream whereas a further increase of the fluorescence intensity is measured in the normal skin with a maximum 240 min p.i. using the gel formulation. The results of the proposed three-compartment model indicate that the observed selectivity of accumulated porphyrins following topical application of ALA is mainly governed by an increased ALA penetration of the stratum corneum of the skin, an accelerated ALA uptake into the cell and a higher porphyrin formation in tumour as compared to normal skin tissue, but not by a reduced ferrocheletase activity.

Curcumin Induces a p53-Dependent Apoptosis in Human Basal Cell Carcinoma Cells

Curcumin, a potent antioxidant and chemopreventive agent, has recently been found to be capable of inducing apoptosis in human hepatoma and leukemia cells by way of an elusive mechanism. Here, we demonstrate that curcumin also induces apoptosis in human basal cell carcinoma cells in a dose- and time-dependent manner, as evidenced by internucleosomal DNA fragmentation and morphologic change. In our study, consistent with the occurrence of DNA fragmentation, nuclear p53 protein initially increased at 12 h and peaked at 48 h after curcumin treatment. Prior treatment of cells with cycloheximide or actinomycin D abolished the p53 increase and apoptosis induced by curcumin, suggesting that either de novo p53 protein synthesis or some proteins synthesis for stabilization of p53 is required for apoptosis. In electrophoretic mobility gel-shift assays, nuclear extracts of cells treated with curcumin displayed distinct patterns of binding between p53 and its consensus binding site. Supportive of these findings, p53 downstream targets, including p21(CIP1/WAF1) and Gadd45, could be induced to localize on the nucleus by curcumin with similar p53 kinetics. Moreover, we immunoprecipitated extracts from basal cell carcinoma cells with different anti-p53 antibodies, which are known to be specific for wild-type or mutant p53 protein. The results reveal that basal cell carcinoma cells contain exclusively wild-type p53; however, curcumin treatment did not interfere with cell cycling. Similarly, the apoptosis suppressor Bcl-2 and promoter Bax were not changed with the curcumin treatment. Finally, treatment of cells with p53 antisense oligonucleotide could effectively prevent curcumin-induced intracellular p53 protein increase and apoptosis, but sense p53 oligonucleotide could not. Thus, our data suggest that the p53-associated signaling pathway is critically involved in curcumin-mediated apoptotic cell death. This evidence also suggests that curcumin may be a potent agent for skin cancer prevention or therapy.

Cytotoxic T cells in basal cell carcinomas of skin.

Previous studies have suggested the importance of CD8+ cytotoxic T-cells of hosts against neoplasms. Earlier studies and our previous investigation showed that a majority of tumor infiltrating T-cells in human basal cell carcinomas (BCCs) belonged to CD4+ T-cells. CD8+ cells were also present in the peritumor areas of human BCCs, but in smaller numbers. Published evidence indicates the importance of cytotoxic T-cells in antitumor immunity. Cytotoxic T-cells have been identified by using monoclonal antibodies against various cytotoxic T-cell components. In this study, we used monoclonal antibodies to perforin to evaluate the role of cytotoxic T-cells in the host response against basal cell carcinomas. Perforin-expressing T-cells could be identified in the infiltrate of BCCs in frozen tissue sections, and also in antigen-retrieved paraffin-embedded sections of BCCs, and the presence of perforin-expressing T-cells correlated with the infiltration of CD8+ T-cells. These results suggest that cytotoxic T-cells play a role in host defense against human BCCs.

Single-cell genetic analysis of the p%3 gene in human basal cell carcinoma(BCC)

Single-cell genetic analysis of the p%3 gene in human basal cell carcinoma(BCC)

Protoporphyrin IX Fluorescence Induced in Basal Cell Carcinoma by Oral δ‐Aminolevulinic Acid*

ABSTRACTLimited depth of penetration significantly limits photodynamic therapy of nodular basal cell carcinoma (BCC) using topical δ(5)‐aminolevulinic acid (ALA). To demonstrate safety and efficacy of orally administered ALA in inducing endogenous protoporphyrin IX (PpIX) production in BCC, 13 patients with BCC ingested ALA in a dose‐escalation protocol. All dose ranges (10, 20 or 40 mg/kg single doses) resulted in formation of PpIX in human skin and BCC, measurable by in vivo fluorescence spectrophotometry. The PpIX fluorescence peaked in tumors before normal adjacent skin from 1 to 3 h after ALA ingestion. Gross fluorescence imaging of ex vivo specimens revealed greater PpIX fluorescence in tumor than normal skin only at the 40 mg/kg dose. Fluorescence microscopy confirmed this finding by showing distinct, full‐thickness PpIX fluorescence in all subtypes of BCC only after ALA given at 40 mg/kg. Side effects were dose dependent and self limited. Photosensitivity lasting less than 24 h and nausea coinciding with peak skin PpIX fluorescence occurred at 20 and 40 mg/kg doses. After 40 mg/kg ALA, serum hepatic enzyme levels rose to a maximum within 24 h, then resolved over 1–3 weeks. Transient bilirubinuria occurred in two patients.