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Abnormal Expression of the p53 Tumor Suppressor Gene in the Conjunctiva of Patients With Pterygium
Abnormal Expression of the p53 Tumor Suppressor Gene in the Conjunctiva of Patients With Pterygium Donald T. H. Tan, FRCS, Arthur S. M. Lim, FRCS, Hak-Su Goh, FRCS, and Duncan R. Smith, PhD PURPOSE: To determine whether pterygium is a disorder of abnormal growth by examining the expression of the p53 gene in the conjunctiva of patients with pterygium. METHODS: Immunostaining for abnormal expres sion of p53 was performed using mouse monoclon al antibody to human p53, pAb 240, on six eyes with primary pterygium and two eyes with recur rent pterygium. RESULTS: In three of the eight eyes with pterygi um, specimens were positive for abnormal expres sion in the epithelium of the pterygium and in the superior bulbar conjunctiva. CONCLUSION: Abnormal p53 expression in the epithelium of primary and recurrent pterygium specimens suggests that pterygium is a growth disorder rather than a degeneration.
T
HE CAUSE OF PTERYGIUM IS UNCERTAIN. SOME FEA-
tures of pterygium suggest tumor-like properties. For example, pterygium can recur aggressively after surgical excision, and treatment modalities mimic treatments for neoplasia, such as wide excision, adjunctive radiotherapy, and antimitotic chemotherapy. Primary pterygia can also be locally invasive, and the pterygium epithelium exhibits varying degrees of abnormality, ranging from mild dysplasia to carcino ma in situ.1 Ultraviolet radiation, a recognized etiologic factor in skin malignancies, has also been shown epidemiologically to be a notable etiologic factor in occurrences of pterygium.2 Accepted for publication Oct 7, 1996. Singapore National Eye Centre (D.T.H.T., A.S.M.L.) and Molecular Biology Laboratory, Tan Tock Seng Hospital (H.-S.G., D.R.S.). Support ed by grant NMRC/0039/1994 from the Singapore National Medical Research Council. Inquiries to Donald T. H. Tan, FRCS, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore 168751, Republic of Singapore; fax: (65) 3231903; e-mail: [email protected]
404
To determine whether pterygium is a tumor-like growth disorder rather than a degenerative condition, we examined the expression of the most common marker of human neoplastic growth, the p53 tumorsuppressor gene. This gene is thought to act as a transcription factor that activates or represses the expression of growth-controlling genes and is abnor mally expressed in a variety of human cancers3 as well as in actinic skin lesions.4 We performed immunostaining using the mouse monoclonal antibody to human p53, pAb 240, and an avidin-biotin-complex technique on frozen sec tions from eight patients: six eyes with primary pterygium and two eyes with recurrent pterygium. Additionally, staining was performed on eight sam ples of conjunctiva from apparently normal superior bulbar conjunctiva of the same eyes. Eight samples of normal conjunctiva from two fresh donor eyes of two different subjects with no conjunctival pathology were used as negative controls. Two samples of a p53positive colorectal tumor specimen were used as positive controls. Three of eight eyes with pterygium were positive for abnormal p53 expression in the epithelium overlying the pterygium, and these same eyes also tested posi tive for abnormal expression in the superior bulbar conjunctiva (Figure). One of the positive specimens was a recurrent pterygium. No substantial staining was visible in the subepithelial fibrovascular layers in any specimen. Staining was limited to the cytoplasm of the epithelial cells in all cases, and in some instances, heavy staining localized in the perinuclear area. No staining was observed in the negative controls, and positive nuclear staining was observed in the positive controls. The finding of p53 overexpression in the epitheli um of both primary and recurrent pterygium speci mens suggests that pterygium is a growth disorder rather than a degeneration. The pAb 240 is specific for a conformation of p53 termed the "mutant" form and is strongly associated with point mutations at the p53 gene.5 This association implies that the overexpression of p53 in pterygium tissues is a result of point mutations of the p53 gene. This view is supported by conclusive data that ultraviolet light can induce mutations in solar keratosis, Bowen disease, and skin carcinomas.3,4 The abnormal expression of p53, not only in the
AMERICAN JOURNAL OF OPHTHALMOLOGY
MARCH
1997
being retained by subsequent daughter cells spreading elsewhere in the conjunctival sac. Identifying abnormal expression of p53 in pterygi um and the superior conjunctiva may help to provide a rational basis for therapy. Furthermore, better understanding the cause of pterygium may enable physicians to prevent occurrence and recurrence of this potentially blinding ocular disorder. REFERENCES 1. Clear AS, Chirambo MC, Hutt MSR. Solar keratosis, pterygi um, and squamous cell carcinoma of the conjunctiva in Malawi. Br ] Ophthalmol 1979;63:102-109. 2. Moran D], Hollows FC. Pterygium and ultraviolet light: a positive correlation. Br J Ophthalmol 1984;68:343-346. 3. Greenblatt MS, Bennett WP, Hollstein M, Harris CC. Mutations in the p53 tumor suppressor gene: clues to etiology and molecular pathogenesis. Cancer Res 1994;54:4855-4878. 4. Sim CS, Slater SD, McKee PH. Mutant p53 protein is expressed in Bowens disease. Am ] Dermatopathol 1992; 14:195-199. 5. Gannon JV, Greaves R, Iggo R, Lane DP. Activating muta tions in p53 produce a common conformational effect. EMBO J 1990;9:1595-1602.
Superior Tarsal Conjunctival Bullae in Cicatricial Pemphigoid Stephen B. Kaye, MD, Claire E. Morton, FRCOphth, Andrew Needham, FRCOphth, J. Angus Scott, FRCOphth, Allan Watson, FRCOphth, and Paul Hiscott, PhD
Figure. Immunostaining with monoclonal antibody pAb 240 is shown on sections of superior bulbar conjunctiva (A, B) and pterygium (C, D) from one eye. Also shown is negative control staining with pAb 240 on normal conjunctiva from a donor eye (E, F). Immunoreactive p53 stains brown (A, C, E, X100; B, D, F, X400).
epithelium of a pterygium but also in the superior bulbar conjunctiva, an area protected from ultraviolet exposure, suggests a field change in the conjunctival epithelium. Such a change could develop from ultra violet damage to limbal stem cells, the abnormality VOL.123, No. 3
PURPOSE: To document a case of conjunctival bullae in cicatricial pemphigoid. METHODS: We describe patients who developed bullae on the conjunctiva in association with cicatricial pemphigoid. RESULTS: Bullae were found on the superior tarsal conjunctiva of two patients. In the first patient, the bulla persisted over a long period; in the second patient, bullae resolved with scarring. CONCLUSION: Unlike gingival bullae, bullae on the conjunctiva in cicatricial pemphigoid are not well documented in the literature. Although un common, their presence may be a useful diagnostic sign of cicatricial pemphigoid, particularly when the bullae are associated with conjunctival cicatri zation and symblepharon.
BRIEF REPORTS
405
T
HE CAUSE OF PTERYGIUM IS UNCERTAIN. SOME FEA-
tures of pterygium suggest tumor-like properties. For example, pterygium can recur aggressively after surgical excision, and treatment modalities mimic treatments for neoplasia, such as wide excision, adjunctive radiotherapy, and antimitotic chemotherapy. Primary pterygia can also be locally invasive, and the pterygium epithelium exhibits varying degrees of abnormality, ranging from mild dysplasia to carcino ma in situ.1 Ultraviolet radiation, a recognized etiologic factor in skin malignancies, has also been shown epidemiologically to be a notable etiologic factor in occurrences of pterygium.2 Accepted for publication Oct 7, 1996. Singapore National Eye Centre (D.T.H.T., A.S.M.L.) and Molecular Biology Laboratory, Tan Tock Seng Hospital (H.-S.G., D.R.S.). Support ed by grant NMRC/0039/1994 from the Singapore National Medical Research Council. Inquiries to Donald T. H. Tan, FRCS, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore 168751, Republic of Singapore; fax: (65) 3231903; e-mail: [email protected]
404
To determine whether pterygium is a tumor-like growth disorder rather than a degenerative condition, we examined the expression of the most common marker of human neoplastic growth, the p53 tumorsuppressor gene. This gene is thought to act as a transcription factor that activates or represses the expression of growth-controlling genes and is abnor mally expressed in a variety of human cancers3 as well as in actinic skin lesions.4 We performed immunostaining using the mouse monoclonal antibody to human p53, pAb 240, and an avidin-biotin-complex technique on frozen sec tions from eight patients: six eyes with primary pterygium and two eyes with recurrent pterygium. Additionally, staining was performed on eight sam ples of conjunctiva from apparently normal superior bulbar conjunctiva of the same eyes. Eight samples of normal conjunctiva from two fresh donor eyes of two different subjects with no conjunctival pathology were used as negative controls. Two samples of a p53positive colorectal tumor specimen were used as positive controls. Three of eight eyes with pterygium were positive for abnormal p53 expression in the epithelium overlying the pterygium, and these same eyes also tested posi tive for abnormal expression in the superior bulbar conjunctiva (Figure). One of the positive specimens was a recurrent pterygium. No substantial staining was visible in the subepithelial fibrovascular layers in any specimen. Staining was limited to the cytoplasm of the epithelial cells in all cases, and in some instances, heavy staining localized in the perinuclear area. No staining was observed in the negative controls, and positive nuclear staining was observed in the positive controls. The finding of p53 overexpression in the epitheli um of both primary and recurrent pterygium speci mens suggests that pterygium is a growth disorder rather than a degeneration. The pAb 240 is specific for a conformation of p53 termed the "mutant" form and is strongly associated with point mutations at the p53 gene.5 This association implies that the overexpression of p53 in pterygium tissues is a result of point mutations of the p53 gene. This view is supported by conclusive data that ultraviolet light can induce mutations in solar keratosis, Bowen disease, and skin carcinomas.3,4 The abnormal expression of p53, not only in the
AMERICAN JOURNAL OF OPHTHALMOLOGY
MARCH
1997
being retained by subsequent daughter cells spreading elsewhere in the conjunctival sac. Identifying abnormal expression of p53 in pterygi um and the superior conjunctiva may help to provide a rational basis for therapy. Furthermore, better understanding the cause of pterygium may enable physicians to prevent occurrence and recurrence of this potentially blinding ocular disorder. REFERENCES 1. Clear AS, Chirambo MC, Hutt MSR. Solar keratosis, pterygi um, and squamous cell carcinoma of the conjunctiva in Malawi. Br ] Ophthalmol 1979;63:102-109. 2. Moran D], Hollows FC. Pterygium and ultraviolet light: a positive correlation. Br J Ophthalmol 1984;68:343-346. 3. Greenblatt MS, Bennett WP, Hollstein M, Harris CC. Mutations in the p53 tumor suppressor gene: clues to etiology and molecular pathogenesis. Cancer Res 1994;54:4855-4878. 4. Sim CS, Slater SD, McKee PH. Mutant p53 protein is expressed in Bowens disease. Am ] Dermatopathol 1992; 14:195-199. 5. Gannon JV, Greaves R, Iggo R, Lane DP. Activating muta tions in p53 produce a common conformational effect. EMBO J 1990;9:1595-1602.
Superior Tarsal Conjunctival Bullae in Cicatricial Pemphigoid Stephen B. Kaye, MD, Claire E. Morton, FRCOphth, Andrew Needham, FRCOphth, J. Angus Scott, FRCOphth, Allan Watson, FRCOphth, and Paul Hiscott, PhD
Figure. Immunostaining with monoclonal antibody pAb 240 is shown on sections of superior bulbar conjunctiva (A, B) and pterygium (C, D) from one eye. Also shown is negative control staining with pAb 240 on normal conjunctiva from a donor eye (E, F). Immunoreactive p53 stains brown (A, C, E, X100; B, D, F, X400).
epithelium of a pterygium but also in the superior bulbar conjunctiva, an area protected from ultraviolet exposure, suggests a field change in the conjunctival epithelium. Such a change could develop from ultra violet damage to limbal stem cells, the abnormality VOL.123, No. 3
PURPOSE: To document a case of conjunctival bullae in cicatricial pemphigoid. METHODS: We describe patients who developed bullae on the conjunctiva in association with cicatricial pemphigoid. RESULTS: Bullae were found on the superior tarsal conjunctiva of two patients. In the first patient, the bulla persisted over a long period; in the second patient, bullae resolved with scarring. CONCLUSION: Unlike gingival bullae, bullae on the conjunctiva in cicatricial pemphigoid are not well documented in the literature. Although un common, their presence may be a useful diagnostic sign of cicatricial pemphigoid, particularly when the bullae are associated with conjunctival cicatri zation and symblepharon.
BRIEF REPORTS
405