The present invention relates to the diagnosis, prognosis, prediction and/or treatment of cancer, for example breast cancer, lung cancer or colon cancer. The present invention provides methods of diagnosing and/or prognosing cancer, predicting efficacy of treatment for cancer, assessing outcome of treatment for cancer, assessing likelihood of metastasis and/or assessing recurrence of cancer, the methods comprising a) analyzing a biological sample obtained from a subject to determine the presence of one or more target molecules representative of expression of SIGLEC1 and/or CCL8 ; and b) comparing the expression level of SIGLEC1 and/or CCL8 determined in (a) with one or more reference values, wherein whether there is a difference in the expression of SIGLEC1 and/or CCL8 in the sample from the subject or not compared to the one or more reference values is indicative of a clinical indication. The invention further provides related methods for treatment of cancer, kits and assay devices for use in the methods, and methods for identifying molecules for use in treating cancer.