J. Kaur et al., Expression of 70-kDa heat shock protein in oral lesions: marker of biological stress or pathogenicity, ORAL ONCOL, 34(6), 1998, pp. 496-501
We showed differential expression of HSP70 during oral tumorigenesis. The p
recise functional role of HSP70 overexpression in the pathogenesis of betel
and tobacco related oral cancer remains to be determined, To evaluate the
utility of HSP70 as an indicator of the biological stress experienced by tu
mour cells or the malignant potential of oral epithelial lesions and predic
ting clinical outcome, its expression was assessed in different stages of o
ral carcinogenesis by immunohistochemical analysis and correlated with clin
icopathological parameters. Overexpression of HSP70 protein was observed in
38 of 64 (59%) dysplastic lesions and 92 of 125 (74%) oral squamous cell c
arcinomas (SCCs) which included 76 of 105 cases (72%) of primary oral SCCs
and 16 of 20 (80%) of recurrent oral SCCs. A significant correlation of HSP
70 expression was observed with severity of dysplasia (P = 0.0006767), poor
histological differentiation of primary tumours (P = 0.0184348), increase
primary tumour size (P = 0.0221103) and consumption of betel and tobacco (P
< 0.01). Follow-up studies showed that in patients with premalignant lesio
ns the median transition time (premalignancy to malignancy) was significant
ly shorter in HSP70 overexpressing cases than those showing basal level of
HSP70 (P = 0.012). Oral cancer patients with elevated levels of HSP70 showe
d decreased median disease-free survival time (no recurrence/ metastasis) t
han those showing basal HSP70 immunoreactivity (P = 0.0246). The results su
ggest that HSP70 expression may not be a mere marker of biological stress b
ut may also be implicated in the pathogenesis of oral cancer. (C) 1998 Else
vier Science Ltd. All rights reserved.