A method to aid in identifying a familial or sporadic pattern of risk in at least one individual for developing cancer of a mucosal epithelial tissue, the method comprising screening said at least one individual for heterozygosity or homozygosity for a mutation in a gene coding for a Poly-Ig (Fc) receptor or a Poly-Ig-like (Fc) receptor capable of mediating inhibition of cancer cell growth by an immunoglobulin inhibitor. A method of treating an individual so identified includes enhancing the amount of immunoglobulin inhibitor contacting a mucosal epithelial tissue of said individual, and, especially in individuals homozygous for the defective receptor, may also include prophylactic surgery. Other methods include implementation of a risk reduction or prevention program in individuals identified as being at risk.