0251). Table 3 Relationships among tumor depth, histological type, and lymph node metastases Tumor depth Histologic type pN(+) Hazard ratio 95% confidence interval p-value m-sm1 (n = 204) Differentiated 1/72 (1.4%) 1.000       Mixed differentiated 1/31 (3.2%) 2.367 0.092-61.123 0.5527   Mixed undifferentiated 3/22 (13.6%) 11.211 1.351-233.786 0.0251*   Undifferentiated 3/79 (3.8%) 2.803 0.350-57.357 0.3449 sm2 (n = 123) Differentiated 11/41 (26.8%)

1.000       Mixed Selleckchem PF-2341066 differentiated 8/25 (32.0%) 1.283 0.423-3.808 0.6539   Mixed undifferentiated 8/14 (57.1%) 3.636 1.042-13.478 0.0430*   Undifferentiated 10/43 (23.3%) 0.826 0.303-2.230 0.7054 * p < 0.05 Of 123 patients with pT1b2 tumors (sm2 group), 37 had nodal metastases. There was a significant association between depth of tumor invasion and nodal metastases in pT1b tumors. The incidence Ivacaftor manufacturer of nodal metastases was higher in the mixed undifferentiated type group than in the differentiated

type group (p = 0.0430). The pathological characteristics of patients in the pT1a-pT1b1 (m-sm1) group with nodal metastases are shown in Table 4. All four node-positive patients with pT1a tumors had ulceration (Figure 1). The smallest tumor size was 10 mm in diameter. One patient had non-perigastric nodal metastases along the common hepatic artery. Table 4 Pathological characteristics of pT1a and pT1b1 tumors with lymph node metastases Case Tumor depth * Macro type Ulceration Tumor size, mm Histologic type L† V† Number of positive node Follow-up time, months Status 1 m 0-IIc Yes 10 sig, tub2 0 0 1 97 Alive 2 m 0-IIc Yes 42 sig, tub2, muc 0 0 1 7 Alive 3 m 0-IIc Yes 60 sig 0 0 1 82 Alive 4 m 0-IIc Yes 100 sig, por, tub1 1 0 1 25 Alive 5 sm1 0-IIc No 25 tub1 0 0 1 76 Alive 6 sm1 0-IIc Yes 25 tub2, por 2 0 4 37 Alive 7 sm1 0-IIc Yes 31 sig 1 1 11 58 Deceased (bone metastasis) 8 sm1 0-IIc Yes 32 por, sig 1 0 1 20 Alive RAS p21 protein activator 1 * According to the third English edition of the Japanese

Classification of Gastric Carcinoma [4]. † According to the seventh edition of the International Union Against Cancer TNM guidelines [3]. muc = mucinous adenocarcinoma; por = poorly differentiated adenocarcinoma; sig = signet-ring cell carcinoma; tub1 = well differentiated adenocarcinoma; tub2 = moderately differentiated adenocarcinoma. Figure 1 Endoscopic, macroscopic and pathological images of mucosal tumors with lymph node metastases. Four of 161 patients with mucosal tumors had nodal metastases. All of these patients had signet-ring cell carcinomas with ulceration. The smallest tumor was 10 mm in diameter (Case 1). One patient had non-perigastric nodal metastases along the common hepatic artery (Case 2). Only 4 of 45 patients with nodal metastases were diagnosed preoperatively (sensitivity 8.9%, specificity 96.1%). Nine patients had recurrence of cancer, and died.