Mucin production, when heavily sialylated, can promote
cancer cell invasion and
metastasis, and modulate the immune recognition system of the host. To explore the prognostic implication of
sialomucin expression in
lung cancer, we studied 116 patients with
non-small-cell lung cancer (NSCLC).
Tumor specimens were stained immunohistochemically with
monoclonal antibodies (mAbs) against
mucin glycoprotein (17Q2, HMFG2, SM3), and histochemically with
periodic acid-Schiff/
alcian blue to differentiate neutral
mucin from
acid mucin, and with
high-iron diamine/alcian blue to differentiate
sialomucin from
sulfomucin. The expression status of two established molecular prognostic factors, the p53 and erbB-2
oncoproteins, were evaluated immunohistochemically. The staining was performed on two separately archived,
paraffin-embedded
tumor blocks for each patient, with normal lung as a control. Correlations were subsequently made among stains and various clinicopathologic factors. All analyses were blinded, and included Kaplan-Meier survival estimates with Cox proportional hazards regression modeling. Associations were established among
adenocarcinoma histotype and erbB-2 overexpression,
sialomucin expression, and 17Q2 and HMFG2 immunohistochemical positivity (p < 0.05).
Sialomucin expression was closely linked to erbB-2 overexpression (p = 0.01). Significant univariate predictors (p < 0.05) of recurrence and
cancer death were surgical stage, p53 expression, erbB-2 overexpression, and
sialomucin expression. These four factors remained as independent predictors of early recurrence (p < 0.05) after multivariate analysis. For
cancer death prediction, p53 and
sialomucin expression had a marginal effect. We concluded that
sialomucin expression is also a poor
indicator of prognosis, which is associated with erbB-2
oncoprotein overexpression, early postoperative recurrence, and
cancer death in NSCLC.