WHO 2022 classification of penile and scrotal cancers: updates and evolution.

Squamous cell carcinoma (SCC) is the most common malignant tumour of the penis. The 2022 WHO classification reinforces the 2016 classification and subclassifies precursor lesions and tumours into human papillomavirus (HPV)-associated and HPV-independent types. HPV-associated penile intraepithelial neoplasia (PeIN) is a precursor lesion of invasive HPV- associated SCC, whereas differentiated PeIN is a precursor lesion of HPV-independent SCC. Block-type positivity of p16 immunohistochemistry is the most practical daily utilised method to separate HPVassociated from HPVindependent penile SCC. If this is not feasible, the term SCC, not otherwise specified (NOS) is appropriate. Certain histologies that were previously classified as "subtypes" are now grouped, and coalesced as "patterns", under the rubric of usual type SCC and verrucous carcinoma (e.g. usual-type SCC includes pseudohyperplastic and acantholytic/pseudoglandular carcinoma, and carcinoma cuniculatum is included as a pattern of verrucous carcinoma). If there is an additional component of the usual type of invasive SCC (formerly termed hybrid histology), the tumour would be a mixed carcinoma (e.g. carcinoma cuniculatum or verrucous carcinoma with usual invasive SCC); in such cases, reporting of the relative percentages in mixed tumours may be useful. The consistent use of uniform nomenclature and reporting of percentages will inform the refinement of future reporting classification schemes and guidelines/recommendations. The classification of scrotal tumours is provided for the first time in the fifth edition of the WHO Blue book, and it follows the schema of penile cancer classification for both precursor lesions and the common SCC of the scrotum. Basal cell carcinoma of the scrotum may have a variable clinical course and finds a separate mention.

Targeting EGFR and PI3K pathways in ovarian cancer.

BACKGROUND: The epidermal growth factor receptor (EGFR) is expressed in ovarian cancer, but agents targeting this pathway have shown little effect as single agents. This may be due to the presence of alternative pathways, particularly activation of the PI3K/Akt/MTOR pathway. METHODS: We have therefore examined the effect of inhibitors of this pathway (ZSTK474 and sirolimus) in combination with the EGFR inhibitors erlotinib and gefitinib in ovarian cancer primary cell cultures. RESULTS: The single-agent EGFR inhibitors showed little activity, although some activity was seen with the single-agent PI3K inhibitor, ZSTK474. Combinations of ZSTK474 with EGFR inhibitors showed enhanced activity with some evidence of synergy, whereas sirolimus combinations were less active. The results were not explicable on the basis of PIK3CA mutation or amplification, or PTEN loss, although one tumour with a KRAS mutation showed resistance to EGFR inhibitors. However, there was correlation of the EGFR expression with sensitivity to EGFR and resistance to PI3K active agents, and inverse correlation in the sensitivity of individual tumours to agents active against these pathways, suggesting a mechanism of action for the combination. CONCLUSION: Phase I/II clinical trials with these agents should include further pharmacodynamic endpoints and molecular characterisation to identify patients most likely to benefit from this strategy.

Identification of markers of prostate cancer progression using candidate gene expression.

BACKGROUND: Metastatic prostate cancer (PCa) has no curative treatment options. Some forms of PCa are indolent and slow growing, while others metastasise quickly and may prove fatal within a very short time. The basis of this variable prognosis is poorly understood, despite considerable research. The aim of this study was to identify markers associated with the progression of PCa. METHODS: Artificial neuronal network analysis combined with data from literature and previous work produced a panel of putative PCa progression markers, which were used in a transcriptomic analysis of 29 radical prostatectomy samples and correlated with clinical outcome. RESULTS: Statistical analysis yielded seven putative markers of PCa progression, ANPEP, ABL1, PSCA, EFNA1, HSPB1, INMT and TRIP13. Two data transformation methods were utilised with only markers that were significant in both selected for further analysis. ANPEP and EFNA1 were significantly correlated with Gleason score. Models of progression co-utilising markers ANPEP and ABL1 or ANPEP and PSCA had the ability to correctly predict indolent or aggressive disease, based on Gleason score, in 89.7% and 86.2% of cases, respectively. Another model of TRIP13 expression in combination with preoperative PSA level and Gleason score was able to correctly predict recurrence in 85.7% of cases. CONCLUSION: This proof of principle study demonstrates a novel association of carcinogenic and tumourigenic gene expression with PCa stage and prognosis.

Circulating tumour markers can define patients with normal colons, benign polyps, and cancers.

BACKGROUND: Early diagnosis represents the best opportunity for cure of colorectal cancer. Current screening programmes use faecal occult blood testing for screening, which has limited sensitivity and poor specificity. METHODS: In this study we looked at a series of previously described diagnostic markers utilising circulating free DNA (cfDNA), with a preparation method allowing small DNA fragments to be isolated. The Circulating free DNA was isolated from samples obtained from 85 patients, including 35 patients without endoscopic abnormality, a group of 26 patients with benign colorectal adenomas, and 24 patients with colorectal carcinomas. In each case, polymerase chain reaction (PCR) was performed for Line1 79 bp, Line1 300 bp, Alu 115 bp, Alu 247 bp, and mitochondrial primers. In addition, carcinoembryonic antigen (CEA) was measured by ELISA. Each marker was analysed between normal, polyp, and cancer populations, and the best performing analysed in combination by logistic regression. RESULTS: The best model was able to discriminate normal from populations with adenoma or carcinoma using three DNA markers and CEA, showing an area under the receiver operator characteristic (ROC) curve of 0.855 with a positive predictive value of 81.1% for polyps and cancer diagnosis. CONCLUSION: These circulating markers in combination with other markers offer the prospect of a simple blood test as a possible secondary screen for colorectal cancers and polyps in patients with positive faecal occult blood tests.

Molecular basis of chemosensitivity of platinum pre-treated ovarian cancer to chemotherapy.

BACKGROUND: Ovarian cancer shows considerable heterogeneity in its sensitivity to chemotherapy both clinically and in vitro. This study tested the hypothesis that the molecular basis of this difference lies within the known resistance mechanisms inherent to these patients' tumours. METHODS: The chemosensitivity of a series of 31 ovarian tumours, all previously treated with platinum-based chemotherapy, was assessed using the ATP-based tumour chemosensitivity assay (ATP-TCA) and correlated with resistance gene expression measured by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) in a TaqMan Array following extraction of mRNA from formalin-fixed paraffin-embedded tissue. The results were standardised against a housekeeping gene (PBGD), and assessed by multiple linear regression. RESULTS: Predictive multiple linear regression models were derived for four single agents (cisplatin, gemcitabine, topotecan, and treosulfan), and for the combinations of cisplatin+gemcitabine and treosulfan+gemcitabine. Particularly strong correlations were obtained for cisplatin, gemcitabine, topotecan, and treosulfan+gemcitabine. No individual gene expression showed direct correlation with activity in the ATP-TCA. Genes involved in DNA repair and apoptosis were strongly represented, with some drug pumps also involved. CONCLUSION: The chemosensitivity of ovarian cancer to drugs is related to the expression of genes involved in sensitivity and resistance mechanisms.

Observational and cost analysis of the implementation of breast cancer sentinel node intraoperative molecular diagnosis.

BACKGROUND: Accurate intraoperative sentinel lymph node (SLN) assessment enables axillary clearance to be completed immediately in node-positive breast cancer patients. This article reports a study of the introduction of intraoperative molecular SLN analysis in routine clinical practice in the Portsmouth Breast Care Centre. DESIGN: There was prospective analysis of 254 consecutive patients who underwent SLN biopsy in a single centre. Nodes were sectioned at 2 mm intervals and alternate slices were analysed using a CE-marked assay for mammaglobin (MG) and cytokeratin 19 (CK19). Remaining slices of node were sent for histological analysis, which included CK19 immunohistochemistry. While the assay was being carried out, the surgeon performed the breast tumour resection. The cost per patient was estimated retrospectively and the cost effects on the hospital and primary care trust for a typical service were also estimated. RESULTS: A total of 491 SLNs from 254 patients were evaluated. The intraoperative assay showed positivity of SLNs for metastatic cells in 78 patients. There was 100% detection of macrometastases within sentinel nodes analysed by GeneSearch. Overall concordance between histological status, including micrometastases and GeneSearch analysis, was 95% (sensitivity 96%, specificity 95%). The cost per procedure was increased for wide local excision with SLN biopsy and intraoperative assessment compared with other models, but fewer procedures were carried out. CONCLUSION: Intraoperative assessment of SLNs in breast cancer using a molecular assay is a safe, acceptable and accurate technique that allows a reduction in the frequency of delayed axillary clearance surgery. Take-up of this method may be hampered by perverse incentives operating within healthcare funding.

Epidemiological characteristics, predisposing factors and microbiological profiles of infectious corneal ulcers: the Portsmouth corneal ulcer study.

AIM: The aim of the study was to identify the epidemiological characteristics, predisposing factors, and the clinical and microbiological diagnosis of infectious corneal ulcers in a population based in southern England. METHODS: A retrospective review was undertaken of the medical records of patients presenting with infectious corneal ulcers at the eye casualty department of Queen Alexandra Hospital, Portsmouth, UK, between January 1997 and December 2003. RESULTS: A total of 1786 patients presented with infectious corneal ulcers, with a mean age of 45 years and female predominance (54.5%). Contact lens wear was the main predisposing factor in 554 patients (31%). Corneal scrapes from 1254 patients grew positive cultures in 800 patients. Gram-positive bacteria accounted for 696 (71.1%) of the total 979 bacterial isolates, while Gram-negative bacteria accounted for 283 (28.9%) with the predominance of Pseudomonas aeruginosa. Nine out of 11 patients with Acanthamoeba keratitis were contact lens wearers. The majority of patients 1728 (96.8%) sought medical help more than once and 34 patients (1.9%) had poor visual outcome. Follow-up was completed in 1633 patients (91.4%) with an average of 11.5 days. CONCLUSIONS: Wearing contact lenses remains the most important risk factor for infectious corneal ulcers. Reduction of the rate and severity of infectious keratitis requires continuous education of patients, and of professionals.

Concentration of haemodynamic and inflammatory related cytokines in diabetic retinopathy.

AIM: There are changes in blood flow during the clinical stages of diabetic retinopathy with increasing leukostasis and secondary elaboration of cytokines. This study evaluated the vitreous concentrations of haemodynamic-related (endothelin-1 (ET-1) and nitric oxide (NO)), inflammatory and anti-inflammatory (interleukin-1 receptor antagonist, IL-1 Ra) cytokines in the diabetic patients (with nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR)), compared them with those of control patients (full thickness macular hole, FTMH) and correlated to macular structural indices. METHOD: Vitreous samples from five FTMH patients representing normal controls were analysed together with the vitreous samples of 15 patients with NPDR and five with PDR. The vitreous concentrations of nitrite (total NO), ET-1, and prostacyclin was determined using ELISA kits (R&D Systems, Minneapolis, MN, USA) according to the manufacturer's instructions. A sandwich luminescent immunoassay technique was used to determine IL-1beta and IL-1 Ra concentrations. RESULTS: In the different clinical groups, there were no differences in the vitreous NO and prostacyclin concentrations. In NPDR, the median ET-1 concentration (0.7 pg/ml SD +/-0.8 pg/ml) was significantly reduced (P<0.05), compared to PDR (6.35 pg/ml SD +/-0.6 pg/ml) and FTMH (3.6 pg/ml SD +/-0.14 pg/ml). Its concentration also positively correlated with foveal thickness and macular volume (P<0.05) in patients with NPDR and macular oedema. IL-1 beta was detected in PDR, and diabetic patients demonstrated a lower concentration of the anti-inflammatory cytokine IL-1 Ra. CONCLUSION: Reduced concentrations of ET-1 in NPDR may reflect the haemodynamic changes of NPDR. The IL-1 Ra concentration suggests a change in the anti-inflammatory environment of the diabetic retina.

Mechanisms of local immunosuppression in cutaneous melanoma.

Cutaneous melanoma is highly immunogenic, yet primary melanomas and metastases develop successfully in otherwise immunocompetent patients. To investigate the local immunosuppressive microenvironment, we examined the presence of suppressor T lymphocytes and tolerising dendritic cells (DCs), the expression of immunosuppressive cytokines (IL-10, TGFbeta1 and TGFbeta2) and the enzyme indoleamine 2,3-dioxygenase (IDO) using qRT-PCR and immunohistochemistry in primary skin melanomas, negative and positive sentinel lymph nodes (SLN), and lymph nodes with advanced metastases. Our results indicate that tolerogenic DCs and suppressor T lymphocytes are present in melanoma at all stages of disease progression. They express transforming growth factor beta receptor 1 (TGFbetaR1), and are therefore susceptible to TGFbeta1 and TGFbeta2 specifically expressed by primary melanoma. We found that expression of IDO and interleukin 10 (IL-10) increased with melanoma progression, with the highest concentration in positive SLN. We suggest that negative SLN contain immunosuppressive cells and cytokines, due to preconditioning by tolerogenic DCs migrating from the primary melanoma site to the SLN. In primary melanoma, TGFbeta2 is likely to render peripheral DCs tolerogenic, while in lymph nodes IDO and TGFbeta1 may have a major effect. This mechanism of tumour-associated immunosuppression may inhibit the immune response to the tumour and may explain the discrepancy between the induction of systemic immunity by anti-melanoma vaccines and their poor performance in the clinic.

Diabetic cataract removal: postoperative progression of maculopathy--growth factor and clinical analysis.

BACKGROUND: Diabetic cataract extraction can be frequently complicated by macular oedema, progression of retinopathy, or development of iris neovascularisation. The pathogenesis of these complications may be the result of changes in the concentration of angiogenic and anti-angiogenic cytokines in the immediate postoperative period. The study aims to prospectively analyse this. METHODS: Uneventful phacoemulsification with intraocular lens implant was performed in seven eyes of six patients with diabetic retinopathy ranging from severe non-proliferative to quiescent proliferative. Patients were reviewed 1 day, 1 week, 1 month, and 3 months after surgery with fundus fluorescein angiography (FFA) and aqueous sampling. Each sample was analysed for VEGF, HGF, Il-1 beta (pg/ml), and PEDF (microg/ml) by sandwich ELISA. RESULTS: Clinically significant macular oedema (CSMO) occurred in one patient although increased macular hyperfluorescence occurred in three patients on FFA at 1 month. VEGF 165 concentration increased 1 day after surgery from a median baseline of 68 pg/ml (range 22-87 pg/ml) to 723 pg/ml (range 336-2071) at day 1. By 1 month it had decreased to 179 (range 66-811 pg/ml). HGF concentrations steadily increased over the month while IL-1 beta and PEDF concentrations demonstrated an acute rise on day 1 after surgery and then IL-1beta returned to baseline concentrations while PEDF decreased to below baseline. CONCLUSION: These results confirm altered concentrations of angiogenic and antiangiogenic growth factors after cataract surgery, which may induce subclinical and clinical worsening of diabetic maculopathy.

Proton beam therapy and iris neovascularisation in uveal melanoma.

PURPOSE: Local treatment of uveal melanoma by radiotherapy involves the use of brachytherapy with radioactive plaques attached to the sclera, or proton irradiation. Both treatments induce growth arrest within the tumour and its slow involution over several years. Although ocular retention rates are excellent, regrowth of tumours due to resistance and neovascular glaucoma leads to enucleation of up to 10% of affected eyes. Proton irradiation involves part of the iris in most cases and we noticed that neovascularisation only occurred in the part of the iris that was not irradiated. We therefore conducted this study to determine the relationship between the development of iris neovascularisation and iris irradiation. METHODS: A total of 21 enucleation specimens from patients who had previously had proton irradiation were collected from the files of the Department of Pathology, Moorfields Eye Hospital during the 5-year period from 1994 to 1999. Sections of these eyes were assessed for VEGF-A, bFGF, and von Willebrand Factor (vWF) by immunohistochemistry. Ophthalmic notes and radiotherapy records were reviewed to assess the extent of iris irradiation. RESULTS: In all, 11 cases showed clinical evidence of iris neovascularisation and were selected for further study. Three of these eyes also showed clinical evidence of regrowth of the tumour. Histological evidence of iris neovascularization was noted in all 11 of the eyes examined, and was only present in the nonirradiated side of the iris in 8/11 eyes. NVI was present on both sides of the iris in three cases, but was less severe in the irradiated part. Expression of VEGF-A was at most weak within the tumour, but was present in the detached retina and in the epithelium of both ciliary body and iris. Some bFGF staining was noted around vessels in the iris stroma. CONCLUSIONS: Our results suggest that irradiation leads to iris atrophy, and that atrophic, irradiated iris is resistant to the development of neovascularisation.

Recruiting donors for autopsy based cancer research.

The use of human tissue for scientific research is a highly sensitive issue. A lack of confidence in patient recruitment is one reason for the failure of many studies to be funded and it is important therefore that recruitment procedures are as effective and sympathetic as possible. The authors recruited patients with uveal melanoma into a postmortem study investigating tumour latency in this cancer. Two approaches were used--firstly a direct approach when patients attended clinic and secondly an initial approach by mail followed by telephone contact. In the first year of study the authors had a take up rate of 88.5%, significantly higher than the average rate of 40% quoted by the National Institute for Clinical Excellence (NICE). Key features are a sympathetic personal approach by experienced oncology nurses, the provision of clear information, and the inclusion of the next of kin in the recruitment procedure.

Phase I trial combining gemcitabine and treosulfan in advanced cutaneous and uveal melanoma patients.

Gemcitabine and treosulfan are DNA-damaging agents. Preclinical studies suggest that synergism exists when melanoma cells are exposed to both drugs concurrently. We conducted a phase I trial in advanced melanoma patients to determine the optimal dose of gemcitabine to be combined with treosulfan. Cohorts of three patients received increasing doses of gemcitabine, commencing at 0.5 g m(-2), followed by a fixed dose of 5.0 g m(-2) treosulfan on day one of a 21-day cycle. Patients alternately received a first cycle of single-agent gemcitabine or treosulfan before subsequent cycles of both drugs. Peripheral blood lymphocytes were collected in cycles 1 and 2 at various time points until 48 h post-treatment. The single-cell gel electrophoresis (Comet) assay was used to measure chemotherapy-induced DNA damage. A total of 27 patients were enrolled, no objective responses were observed, but two uveal melanoma patients had minor responses. Dose-limiting myelosuppression was reached at 3.0 g m(-2) gemcitabine. DNA single-strand breaks were detected 4 h post-gemcitabine, repaired by 24 h. DNA interstrand crosslinks were detected 4 h post-treosulfan, fully removed by 48 h. Following combination chemotherapy, treosulfan-induced DNA crosslinks persisted, still being detectable 48 h post-treatment, supporting the hypothesis that gemcitabine potentiates treosulfan-induced cytotoxicity. The recommended regimen for further study is 2.5 g m(-2) gemcitabine combined with 5.0 g m(-2) treosulfan.

Angiopoietin concentrations in diabetic retinopathy.

BACKGROUND/AIM: Angiopoietin 1 and 2 interact with vascular endothelial growth factor (VEGF) to promote angiogenesis in animal and in vitro models. Although VEGF concentrations are elevated, there is little information regarding angiopoietin concentration in the vitreous of patients with diabetic retinopathy. METHODS: Angiopoietin concentrations were measured by luminescence immunoassay in vitreous samples from 17 patients with non-proliferative diabetic retinopathy (NPDR) and clinically significant diabetic macular oedema (CSMO), 10 patients with proliferative diabetic retinopathy (PDR), and five patients with macular hole (controls) obtained at pars plana vitrectomy. RESULTS: Angiopoietin 1 concentrations were low in patients with macular hole (median 17 pg/ml) while in NPDR with CSMO they were 2002 pg/ml (range 289-5820 pg/ml) and in PDR 186 pg/ml (range 26-2292 pg/ml). Angiopoietin 2 concentrations in NPDR with CSMO were a median of 4000 pg/ml (range 1341-14 329 pg/ml). For both macular hole and PDR patients angiopoietin 2 was below the limit of detection. CONCLUSIONS: Angiopoietin 2 concentration was twice that of angiopoietin 1 in NPDR with CSMO. Angiopoietin 2 is the natural antagonist of angiopoietin 1 which is thought to act as an anti-permeability agent. The predominance of angiopoietin 2 may allow VEGF induced retinal vascular permeability in patients with CSMO. The relatively low concentration of both angiopoietin 1 and 2 in patients with proliferative diabetic retinopathy may reflect the established nature of the neovascularisation in cases proceeding to vitrectomy.

Case of thymic parathyroid carcinoma in a haemodialysis patient: application of tumour chemosensitivity testing.

Parathyroid carcinoma is a rare tumour, which is often difficult to diagnose. This is especially true in patients with pre-existing tertiary hyperparathyroidism of end-stage renal disease. A case is presented of parathyroid carcinoma in a haemodialysis patient with unusual thymic involvement. After demonstrating the difficulty in pre-operative diagnosis and risk of recurrence, the importance of non-surgical treatment options is discussed and the investigation of individual tumour chemosensitivity is introduced, which is new to this type of cancer.

Combination chemotherapy in advanced gastrointestinal cancers: ex vivo sensitivity to gemcitabine and mitomycin C.

Advanced or metastatic disease is common in both oesophagogastric and colorectal cancers, with poor 5-year survival despite palliative chemotherapy. We have investigated the sensitivity of gastrointestinal tumours to gemcitabine in combination with mitomycin C (GeM), using a modified ex vivo ATP-based tumour chemosensitivity assay (ATP-TCA). Tumour material from 41 colorectal and 22 oesophagogastric cancers were assessed. The GeM combination showed variable but definite activity in most of the samples tested. The results show that GeM achieves >95% inhibition at concentrations within the range achievable clinically in 60% of colorectal tumours (21 out of 35) and 38% of oesophagogastric tumours (five out of 13) tested. We did not identify any significant difference in sensitivity using concurrent or sequential exposure of tumour-derived cells to these two drugs. The results from this study suggest that GeM may be a useful combination in the treatment of advanced gastrointestinal malignancy.

A clinical, histopathological, and genetic study of Avellino corneal dystrophy in British families.

AIMS: To establish a clinical, histopathological, and genetic diagnosis in two unrelated British families with Avellino corneal dystrophy (ACD). METHODS: Genomic DNA was extracted from peripheral blood leucocytes of all members participating in the study. Exons 4 and 12 of the human transforming growth factor beta induced (BIGH3) gene were amplified by polymerase chain reaction. The mutation and polymorphism were identified by direct sequencing and restriction digest analysis. A review of the patients' clinical symptoms and signs was undertaken and a histopathological study on corneal specimen obtained from the proband of one family after keratoplasty was performed. RESULTS: A heterozygous G to A transition at the second nucleotide position of codon 124 of BIGH3 gene was detected in all affected members of both families. This mutation changes an arginine residue to a histidine. The clinical diagnosis for ACD was more evident with advancing age. Histopathological study revealed granular deposits in the anterior stroma and occasional positive Congo red areas of amyloid deposition in the mid to deep stroma typical of ACD. CONCLUSIONS: This is the first report of ACD families in the United Kingdom and, furthermore, of BIGH3 gene mutation in British patients with this rare type of corneal dystrophy. The results indicate that BIGH3 gene screening along with clinical and histopathological examinations is essential for the diagnosis and clinical management of corneal dystrophies.

Absence of BRAF gene mutations in uveal melanomas in contrast to cutaneous melanomas.

The recent discovery of activating mutations in the BRAF gene in many cutaneous melanomas led us to screen the genomic sequence of BRAF exons 11 and 15 in a series of 48 intraocular (uveal) melanomas, together with control samples from three cutaneous melanomas and the SK-Mel-28 cell line, which has a BRAF mutation. The same mutation was detected in two-thirds of our cutaneous melanoma samples, but was not present in any uveal melanomas. This finding further underlines the distinction between uveal and cutaneous melanomas, and suggests that BRAF inhibitors are unlikely to benefit patients with uveal melanoma.

Tyr-TGFalpha transgenic mice develop ocular melanocytic lesions.

Transforming growth factor-alpha (TGFalpha) has been implicated in melanocyte transformation, as it is expressed in melanocytic lesions and in melanoma cells. We investigated its role in melanoma development using a transgenic mouse model. The mice were generated by microinjection of a transgene with 270 bp of the mouse tyrosinase promoter and the cDNA for human TGFalpha. No significant skin abnormalities were found, but individuals from three transgenic lines developed ocular melanocytoses (seven out of 10 transgenics), usually after a long latency period. In particular, the melanocyte component of the choroid was thicker than in non-transgenic controls, consistent with hyperplasia. The retinal pigment epithelium was unaffected. Melanocytic lesions were also present in the posterior eye, and abnormal distributions of melanocytes were found in neural tissue of the brain, skeletal muscle of the head and the Harderian glands, indicating migration from the choroid. It was concluded that mice engineered to express the normal growth factor TGFalpha from a tyrosinase promoter spontaneously developed melanocytic lesions in the eye but not the skin.