HER2-neu Expression and Survival in Colorectal Cancer in the South of Egypt; Immunohistochemistry and Genetic Study.

BACKGROUND

Colorectal cancer (CRC) is a major public health problem and one of leading cancer related death all over the world. One of the prognostic parameters that play a role in different types of cancer is HER2. However, the role of HER2 in CRC and its relation with clinicopathological features and survival is conflicting. We hypothesize that HER2 has different patterns of expression in CRC which may affect the prognosis of patients.

MATERIAL &

METHODS

We studied sixty specimens of colorectal carcinoma for HER2 immunohistochemistry and gene amplification and correlate it with clinicopathological features and patients` survival.

RESULTS

Our data showed that negative HER2 expression was statistically associated with female gender (P = 0.010) and low & intermediate tumor budding (P = 0.030). There was a statistically significant relation between HER2 IHC and HER2 FISH amplification (P=0.000). Although neither HER2 immunoexpression and FISH amplification showed significant relation with overall survival nor disease free survival, HER2 amplified CRCs tended to have a worse survival compared with negative CRCs (40 months versus 50 months). The presence of male gender, lymphovascular invasion, nodal metastasis and distant metastasis (P = 0.013, 0.006, 0.006 and 0.000 respectively) were significantly statistically associated with poor overall survival. The presence of tumor grade III and high tumor budding (P = 0.035 and 0.007 respectively) were significantly statistically associated with shorter disease free survival.

CONCLUSIONS

Our results showed that HER2 IHC 3+ staining is highly predictive of HER2 gene amplification in colorectal carcinomas. There is a tendency towards poorer prognosis in amplified HER2 CRC cases.