Stromal p16 Overexpression in Gastric-type Mucinous Carcinoma of the Uterine Cervix.

BACKGROUND/AIM: Gastric-type mucinous carcinoma (MC-G) of the uterine cervix displays distinct morphological features and an aggressive clinical course. The expression status of p16 in the stroma has not been investigated in adenocarcinoma of the uterine cervix. Stromal p16 expression was evaluated in endocervical adenocarcinomas, including usual-type endocervical adenocarcinoma (UEA), intestinal-type mucinous carcinoma (MC-I), and MC-G. Whether stromal p16 expression varied significantly according to the histological subtype and whether the expression status is associated with clinicopathological characteristics of MC-G was also investigated. MATERIALS AND METHODS: Immunostaining of p16 was performed for 24, 19, and 18 cases of UEA, MC-I, and MC-G, respectively. RESULTS: UEA and MC-I subtypes exhibited horizontally continuous, strong nuclear p16 immunoreactivity in the tumor cells, whereas none of the MC-G cases showed diffuse and strong nuclear immunoreactivity for p16 in the tumor cells. Instead, 10 (55.6%) cases of MC-G displayed moderately to strongly positive p16 expression in the stroma. Stromal p16 expression of MC-G was significantly higher than that of normal cervix, UEA, and MC-I. Metastatic MC-G had significantly higher stromal p16 expression than primary MC-G. Further, stromal p16 overexpression in MC-G was associated with advanced stage, parametrial invasion, and lymphovascular invasion. CONCLUSION: Stromal p16 expression of MC-G was significantly higher than that of normal cervix and other histological subtypes of adenocarcinoma and was associated with advanced stage, parametrial invasion, and lymphovascular invasion, reflecting the aggressive behavior of MC-G. Our observations suggest that stromal p16 expression is involved in the development and progression of MC-G.

Expression of phosphorylated extracellular signal-regulated kinase at the invasive front of hepatic colorectal metastasis.

Raf-1 kinase inhibitory protein (RKIP), an endogenous inhibitor of the extracellular signal-regulated kinase (ERK) pathway, suppresses metastasis in a number of cancer types, including colorectal carcinoma (CRC); thus, RKIP downregulation significantly contributes to CRC invasiveness and metastatic potential. However, our previous study demonstrated that RKIP-positive tumors in CRC patients are predictive of hepatic colorectal metastases (HCMs). Based on the previous finding that the ERK pathway can be activated independently of RKIP, we hypothesized that RKIP-expressing HCMs may express significant levels of phosphorylated ERK (pERK). Thus, the present study evaluated the expression of RKIP and pERK in 68 HCM tissue samples using immunohistochemistry. RKIP expression was positive in 22 (32.4%) of the 68 samples, seven (31.8%) of which exhibited nuclear pERK immunoreactivity exclusively at the invasive tumor front. Furthermore, pERK expression at the invasive front was significantly associated with recurrent HCM following hepatic resection, and pERK expression observed at the invasive front of RKIP-expressing HCMs indicated that the activation of the ERK pathway may also be involved in the invasive process of these tumors, despite the presence of RKIP. A strong association between pERK expression and the presence of recurrent HCM may indicate that the ERK pathway is important in the metastatic recurrence of RKIP-positive HCM.