Expression of FXYD-3 is an independent prognostic factor in rectal cancer patients with preoperative radiotherapy.
OBJECTIVE
FXYD-3 (MAT-8) is overexpressed in several types of cancers; however, its clinical relevance in rectal cancers has not been studied. Therefore, we examined FXYD-3 expression in rectal cancers from the patients who participated in a Swedish clinical trial of preoperative radiotherapy (RT) to determine whether FXYD-3 was overexpressed in rectal cancers and correlated with RT, survival, and other clinicopathologic variables.


METHODS
The study included 140 rectal cancer patients who participated in a clinical trial of preoperative RT, 65 with and 75 without RT before surgery. FXYD-3 expression was immunohistochemically examined in distant (n = 70) and adjacent (n = 101) normal mucosa, primary tumors (n = 140), and lymph node metastasis (n = 36).


RESULTS
In the whole cohort, strong FXYD-3 expression was correlated with infiltrative tumor growth (p = 0.02). In the RT group, strong FXYD-3 expression alone (p = 0 .02) or combined with phosphatase of regenerating liver was associated with an unfavorable prognosis (p = 0.02), independent of both TNM stage and tumor differentiation. In tumors with strong FXYD-3 expression, there was less tumor necrosis (p = 0.02) and a trend toward increased incidence of distant metastasis (p = 0.08) after RT. None of these effects was seen in the non-RT group. FXYD-3 expression in the primary tumors tended to be increased compared with normal mucosa regardless of RT.


CONCLUSIONS
FXYD-3 expression was a prognostic factor independent of tumor stage and differentiation in patients receiving preoperative RT for rectal cancer.
Loftås
Per
P
Department of Surgery, Vrinnevi Hospital, Norrköping, Sweden.
Onnesjö
Sofia
S
Widegren
Emma
E
Adell
Gunnar
G
Kayed
Hany
H
Kleeff
Jörg
J
Zentgraf
Hanswalter
H
Sun
Xiao-Feng
XF
D000230:Adenocarcinoma / Q000378:metabolism / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D018797:Cell Cycle Proteins / Q000378:metabolism*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D008207:Lymphatic Metastasis; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D012004:Rectal Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery
D018797:Cell Cycle Proteins; C091777:FXYD3 protein, human; D008565:Membrane Proteins; D009363:Neoplasm Proteins; C490198:PTP4A1 protein, human; D017027:Protein Tyrosine Phosphatases