Epidermal growth factor receptor and c-erbB-2 oncoprotein expression in female genital tract carcinosarcomas (malignant mixed müllerian tumors). Clinicopathologic study of 82 cases.

BACKGROUND

Epidermal growth factor receptor (EGFR) and c-erbB-2 (also known as HER-2/neu) oncoprotein (p185erbB-2) are members of the subfamily of tyrosine kinase, transmembrane receptors often implicated in human carcinogenesis. We hypothesize that expression of EGFR and p185erbB-2 adds useful prognostic and histogenetic information regarding female genital tract carcinosarcomas (FGTCSs).

METHODS

Paraffin sections from 82 FGTCS (61 endometrium, 14 ovary, 5 cervix, and 2 fallopian tube), 56% of which exhibited heterologous elements, were stained using anti-EGFR (clone 31G7, Triton Diagnostics, Alameda, CA) and anti-p185erbB-2 (clone CB11, Novocastra Labs, UK).

RESULTS

EGFR reactivity was present in 11 (13.4%) FGTCSs (55% carcinomatous component [CC] only, 18% sarcomatous component [SC] only, and 27% in both). EGFR was associated with adenosquamous histology of the CC (P < 0.05) and heterologous rhabdomyosarcomatous differentiation in the SC (P < 0.05); no other histopathologic features were correlated. p185erbB-2 reactivity was present in 79 (87.8% strong [S], 78% membrane [M], and 8.5% weak) FGTCSs (1% CC only, 0% SC only, and 99% in both). p185erbB-2 did not correlate with histopathologic features or EGFR. Seventy-seven patients had clinical follow-up for longer than 12 months. Approximately 49.3% and 72.3% of patients had recurrent disease by 12 and 80 months, respectively; all but 1 were dead from disease. 27% of patients were disease free after 15 to 307 months (median, 77 months; mean, 92 months). EGFR, but not p185erbB-2 expression predicted disease recurrence (P < 0.05). Recurrent disease was associated with Stage greater than I (P < 0.0001), vascular space invasion in resection specimens (P < 0.01), and deep myometrial invasion in hysterectomies (P < 0.05). EGFR was associated with Stage greater than I and did not help predict recurrence in good prognosis groups.

CONCLUSIONS

p185erbB-2 overexpression in both CC and SC of FGTCS suggests a common carcinogenic mechanism for both components and supports the conversion-histogenesis hypothesis implicating a dominant role for the CC with the SC arising as a metaplastic change from the CC. EGFR may be expressed in either component and indicates aggressive biologic behavior; however, its prognostic utility is limited by its low predictive value for recurrence (40.3%), inability to foretell recurrence in good prognosis groups, and dependence on stage. High frequency of overexpression and dismal prognosis make FGTCS patients good candidates for trials of therapeutic strategies involving the p185erbB-2 receptor manipulations.